fix(perps): adjust liquidation distance value when zero (MetaMask#24128)

## **Description**

When a position has a liquidation price of $0 (e.g., cross-margin
positions), the Adjust Margin view was displaying "0%" for liquidation
distance, which is misleading since 0% would normally indicate imminent
liquidation.

This PR adds a fallback display ("--") when the liquidation price is $0,
consistent with how other displays handle unavailable data in the Perps
feature.

## **Changelog**

CHANGELOG entry: Fixed liquidation distance showing 0% instead of
fallback when liquidation price is unavailable

## **Related issues**

Fixes: https://consensyssoftware.atlassian.net/browse/TAT-2200

## **Manual testing steps**

```gherkin
Feature: Adjust Margin View - Liquidation Distance Display

  Scenario: User views liquidation distance when liquidation price is $0
    Given user has an open position with liquidation price of $0

    When user opens the Adjust Margin view
    Then liquidation distance displays "--" instead of "0%"

  Scenario: User views liquidation distance with valid liquidation price
    Given user has an open position with a valid liquidation price

    When user opens the Adjust Margin view
    Then liquidation distance displays the correct percentage (e.g., "25%")
```

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

<!-- Liquidation distance shows "0%" when liquidation price is $0 -->
<img width="1206" height="2622" alt="Simulator Screenshot -
iPhone16Pro-Gamma - 2025-12-18 at 11 44 31"
src="https://github.com/user-attachments/assets/d0a5a7f1-d53d-4c0e-820b-cb54110d6404"
/>

### **After**

<img width="1206" height="2622" alt="Simulator Screenshot -
iPhone16Pro-Delta - 2025-12-18 at 11 47 32"
src="https://github.com/user-attachments/assets/ad72b39b-c58c-486f-a398-c1e755010cf7"
/>

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Use a formatter to display a fallback (e.g., "--") for liquidation
distance when liquidation price is 0 in the Adjust Margin view.
> 
> - **Perps Adjust Margin View (`PerpsAdjustMarginView.tsx`)**:
>   - **Liquidation Distance**:
> - Add `formatLiquidationDistance` helper to return
`PERPS_CONSTANTS.FALLBACK_DATA_DISPLAY` when `liquidationPrice === 0`.
> - Replace direct percentage rendering with `formatLiquidationDistance`
for current and new values.
>   - **Config**: Import `PERPS_CONSTANTS` from `constants/perpsConfig`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
3c7f695. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: abretonc7s

app/components/UI/Perps/Views/PerpsAdjustMarginView/PerpsAdjustMarginView.tsx

@@ -40,6 +40,7 @@ import {
   PRICE_RANGES_UNIVERSAL,
   PRICE_RANGES_MINIMAL_VIEW,
 } from '../../utils/formatUtils';
+import { PERPS_CONSTANTS } from '../../constants/perpsConfig';
 
 interface AdjustMarginRouteParams {
   position: Position;
@@ -152,6 +153,17 @@ const PerpsAdjustMarginView: React.FC = () => {
     setSelectedTooltip(null);
   }, []);
 
+  // Helper to format liquidation distance with fallback when liquidation price is unavailable
+  const formatLiquidationDistance = useCallback(
+    (distance: number, liquidationPrice: number): string => {
+      if (liquidationPrice === 0) {
+        return PERPS_CONSTANTS.FALLBACK_DATA_DISPLAY;
+      }
+      return `${distance.toFixed(0)}%`;
+    },
+    [],
+  );
+
   const handleConfirm = useCallback(async () => {
     if (marginAmount <= 0 || !position) return;
 
@@ -347,20 +359,29 @@ const PerpsAdjustMarginView: React.FC = () => {
                   variant={TextVariant.BodyMD}
                   color={TextColor.Alternative}
                 >
-                  {currentLiquidationDistance.toFixed(0)}%
+                  {formatLiquidationDistance(
+                    currentLiquidationDistance,
+                    currentLiquidationPrice,
+                  )}
                 </Text>
                 <Icon
                   name={IconName.Arrow2Right}
                   size={IconSize.Sm}
                   color={colors.icon.alternative}
                 />
                 <Text variant={TextVariant.BodyMD}>
-                  {newLiquidationDistance.toFixed(0)}%
+                  {formatLiquidationDistance(
+                    newLiquidationDistance,
+                    newLiquidationPrice,
+                  )}
                 </Text>
               </View>
             ) : (
               <Text variant={TextVariant.BodyMD}>
-                {currentLiquidationDistance.toFixed(0)}%
+                {formatLiquidationDistance(
+                  currentLiquidationDistance,
+                  currentLiquidationPrice,
+                )}
               </Text>
             )}
           </View>