fix: Address lint errors in a11y changes

- Prettier: break AttachmentRow props onto separate lines
- no-empty-function: use named noOp instead of inline empty arrow
- require-unicode-regexp: add 'u' flag to regex
- no-magic-numbers: extract ARIA_LABEL_MAX_LENGTH constant

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: uzirthapa

packages/bundle/src/adaptiveCards/Attachment/AdaptiveCardHacks/useRoleModEffect.ts

@@ -5,6 +5,11 @@ import useAdaptiveCardModEffect from './private/useAdaptiveCardModEffect';
 
 import type { AdaptiveCard } from 'adaptivecards';
 
+const ARIA_LABEL_MAX_LENGTH = 200;
+
+// eslint-disable-next-line no-empty-function -- initialized as no-op, reassigned when aria-label is set
+const noOp = () => {};
+
 /**
  * Accessibility: "role" attribute must be set if "aria-label" is set.
  *
@@ -37,13 +42,16 @@ export default function useRoleModEffect(
     () => (_, cardElement: HTMLElement) => {
       // If the card doesn't have an aria-label (i.e. no "speak" property was set),
       // derive one from the card's visible text content so screen readers can announce it.
-      let undoAriaLabel: () => void = () => {};
+      let undoAriaLabel: () => void = noOp;
 
       if (!cardElement.getAttribute('aria-label')) {
-        const textContent = (cardElement.textContent || '').replace(/\s+/g, ' ').trim();
+        const textContent = (cardElement.textContent || '').replace(/\s+/gu, ' ').trim();
 
         if (textContent) {
-          const label = textContent.length > 200 ? textContent.slice(0, 200) + '\u2026' : textContent;
+          const label =
+            textContent.length > ARIA_LABEL_MAX_LENGTH
+              ? textContent.slice(0, ARIA_LABEL_MAX_LENGTH) + '\u2026'
+              : textContent;
 
           undoAriaLabel = setOrRemoveAttributeIfFalseWithUndo(cardElement, 'aria-label', label);
         }

packages/component/src/Activity/AttachmentRow.tsx

@@ -35,7 +35,12 @@ function AttachmentRow(props: AttachmentRowProps) {
   const classNames = useStyles(styles);
 
   return (
-    <div aria-roledescription="attachment" className={classNames['stacked-layout__attachment-row']} role="group" tabIndex={0}>
+    <div
+      aria-roledescription="attachment"
+      className={classNames['stacked-layout__attachment-row']}
+      role="group"
+      tabIndex={0}
+    >
       <ScreenReaderText text={attachedAlt} />
       {showBubble ? (
         <Bubble