Fix memory leak in ReanimatedSwipeable on programmatic close (#3790)

# Fix memory leak in ReanimatedSwipeable on programmatic close

  ## Problem

  ReanimatedSwipeable experiences a performance leak when closing
  programmatically via `.close()` or triggered by child content
  interaction. The UI thread produces infinite updates even after the
  spring animation visually finishes.

  ### Symptoms
  - Infinite UI thread updates when calling `.close()` programmatically
  - Animation appears complete but background processing continues
  indefinitely
  - Issue only occurs with programmatic closure, not manual swipe
  gestures
  - Affects iOS with react-native 0.81.0+ and gesture-handler 2.29.0

  ## Root Cause

  The `animateRow` function accepts an optional `velocityX` parameter:
  ```typescript
  const animateRow = (toValue: number, velocityX?: number) => {
  ```
  When closing programmatically, no velocity value is provided,
  resulting in velocityX = undefined.

  The spring animation configuration requires numeric velocity values
  to:
  1. Calculate motion trajectory - how the value changes over time
  2. Detect convergence - when animation should stop based on
  restSpeedThreshold and restDisplacementThreshold

  With undefined velocity:
  - Spring cannot properly evaluate convergence conditions
  - Animation loop never detects it should terminate
  - UI thread continues updating indefinitely

  Manual swipes work fine because gesture handlers provide actual
  velocity values (e.g., -300, 150), ensuring valid numeric input.

  Solution

  Set a default parameter value for velocityX:
  ```typescript
  const animateRow = (toValue: number, velocityX = 0) => {
  ```

  This ensures:
  - velocityX is always a number, never undefined
  - Spring animation receives valid initial velocity of 0 (no momentum)
  - Convergence detection works correctly - animation stops when
  position settles
  - Single point of fix at function signature level (cleaner than
  multiple nullish coalescing checks)

  Testing

  - Programmatic .close() no longer causes infinite updates
  - Manual swipe gestures continue to work correctly
  - Animation behavior remains unchanged visually


Video from the same repo: 
https://youtu.be/qqS_ZfSU7NI

Author: kulak91

packages/react-native-gesture-handler/src/components/ReanimatedSwipeable/ReanimatedSwipeable.tsx

@@ -203,7 +203,7 @@ const Swipeable = (props: SwipeableProps) => {
   );
 
   const animateRow: (toValue: number, velocityX?: number) => void = useCallback(
-    (toValue: number, velocityX?: number) => {
+    (toValue: number, velocityX = 0) => {
       'worklet';
 
       const translationSpringConfig = {