[iOS] Fix EG2 tests by modifying helper

This CL changes the matcher for the Close button, making sure that it
is enabled.

Bug: 1013542
Change-Id: Ibf971693cbd6f8615c64a795d76c5b6db9ad5093
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1855823Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705050}

ios/chrome/test/earl_grey/chrome_matchers_app_interface.mm

@@ -224,8 +224,9 @@ UIView* SubviewWithAccessibilityIdentifier(NSString* accessibility_id,
 }
 
 + (id<GREYMatcher>)closeButton {
-  return
-      [ChromeMatchersAppInterface buttonWithAccessibilityLabelID:(IDS_CLOSE)];
+  return grey_allOf(
+      [ChromeMatchersAppInterface buttonWithAccessibilityLabelID:(IDS_CLOSE)],
+      grey_not(grey_accessibilityTrait(UIAccessibilityTraitNotEnabled)), nil);
 }
 
 + (id<GREYMatcher>)forwardButton {