Change AccessibilitySettingsTest to use Batch.PER_CLASS.

This test was originally not batched at all. Tried to go the opposite extreme, but started to see flakiness. 

As a first step, dial it down to batch per class. If this still causes issues, then we need to turn off batching entirely (i.e. @DoNotBatch(reason = "..."))

Bug: 448783454
Change-Id: Ib5da2551a22c034eab4965098b5414dd76855798
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7062051
Commit-Queue: Wenyu Fu <[email protected]>
Reviewed-by: Wenyu Fu <[email protected]>
Auto-Submit: Eric Lok <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1532377}

Author: ericbklok

components/browser_ui/accessibility/android/java/src/org/chromium/components/browser_ui/accessibility/AccessibilitySettingsTest.java

@@ -73,7 +73,7 @@
     ContentFeatureList.ACCESSIBILITY_PAGE_ZOOM_V2,
     ContentFeatureList.SMART_ZOOM
 })
-@Batch(Batch.UNIT_TESTS)
+@Batch(Batch.PER_CLASS)
 public class AccessibilitySettingsTest {
     private AccessibilitySettings mAccessibilitySettings;