feat(A11yFeedback): Add FeedbackManager for Accessibility page

This change introduces a new FeedbackManager class to identify and
determine the availability of user feedback. This API will be used
to check if feedback is available for a user to provide.

Bug: 393980229
Test: atest FeedbackManagerTest
Flag: com.android.server.accessibility.enable_low_vision_generic_feedback
Change-Id: I577aa626c18f5c449dc3970d1324cc4940d20639