Refactoring A11y shortcut functions in Settings to use GESTURE

Properly integrating GESTURE into Settings, so that text pertaining to the gesture shortcut are displayed when appropriate.
Heavy refactoring has been done to allow for easier cleanup and expansion

Demo video: https://x20web.corp.google.com/users/jo/jonesriley/splitShortcut/a11ySettingsGestureCompat.mp4

NO_IFTTT=changes do not alter the order of the shortcuts.

Bug: 365570709
Test: atest com.android.settings.accessibility
Flag: android.provider.a11y_standalone_gesture_enabled
Change-Id: If90719763a48e3b8bc35988a1de9a352a766953b