Release the A11yManagerService#mLock before calling WMS#addWindowToken.

To enable the flag:
  adb shell device_config put accessibility \
  com.android.server.accessibility.add_window_token_without_lock true

Bug: 297972548
Test: Perform the below tests with flag disabled & enabled...
Test: Use a service with an overlay; observe behavior is unchanged
Test: atest CtsAccessibilityServiceTestCases
Test: atest FrameworksServicesTests:com.android.server.accessibility
Change-Id: I8599bc9bf26ba86c9aef35cf027408868cfece53