feat(MultiFingerMultiTap): Add a feature flag and update its value from...

feat(MultiFingerMultiTap): Add a feature flag and update its value from observing the settings value for AccessibilityInputFilter

Add a feature flag and update its value from observing the settings value, so that  magnification gesture handler will be update once gesture change. Then settings value ACCESSIBILITY_DISPLAY_MAGNIFICATION_ENABLED will be replaced ACCESSIBILITY_MAGNIFICATION_GESTURE once the feature completement.

Bug: 297805269
Test: manual
Change-Id: I9e83a2bdccd1e1f73389eccb606f2dff807c6cd2