Update a11y shortcut images

- Update QS, gesture, volume keys shortcut type images
- Change FAB image to animated image
- Change 2-finger double tap, triple tap animated images
- Fix the alpha value set in the FAB preview

Bug: 324312956
Test: Run and view the images
Test: atest com.android.settings.accessibility
Flag: EXEMPT low risk, resource change
Change-Id: Ic0f1953ca20fc8a3dc7b684f95ee18dae67c4f09