Use IS_FROM_SLICE extra on accessibility intent

The slices UX in settings is designed for deep links from slices, where
settings deeplinks are fired from within settings.  This is the same UX
that SafetyCenterSources follows, so by setting this Intent we use the
same experience that settings team designs for these internal deeplinks.

Test: manually
Test: atest PermissionControllerMockingTests CtsPermissionTestCases
Relnote: N/A
Bug: 258188750
Change-Id: I47aff634e5f0ab6ff02f182fc5291b9d4ea1c107