Fix lint and format errors in UnderlineNav changes

Co-authored-by: jonrohan <54012+jonrohan@users.noreply.github.com>

Author: Copilot

packages/react/src/UnderlineNav/UnderlineNav.test.tsx

@@ -202,7 +202,7 @@ describe('UnderlineNav', () => {
     render(
       <UnderlineNav aria-label="Repository">
         <UnderlineNav.Item className="custom-class">Item 1</UnderlineNav.Item>
-      </UnderlineNav>
+      </UnderlineNav>,
     )
     const item = screen.getByRole('link', {name: 'Item 1'})
     expect(item.className).toContain('custom-class')

packages/react/src/internal/components/UnderlineTabbedInterface.tsx

@@ -107,11 +107,11 @@ export const UnderlineItem = forwardRef(
     forwardedRef,
   ) => {
     return (
-      <BoxWithFallback 
-        ref={forwardedRef} 
-        as={as} 
-        sx={sxProp} 
-        className={clsx(classes.UnderlineItem, className)} 
+      <BoxWithFallback
+        ref={forwardedRef}
+        as={as}
+        sx={sxProp}
+        className={clsx(classes.UnderlineItem, className)}
         {...rest}
       >
         {iconsVisible && Icon && <span data-component="icon">{isElement(Icon) ? Icon : <Icon />}</span>}