Add new floating action menu for Accessibility targets. (2/n)

Patch action:
1. Update the style depends on the settings icon and size key.
2. Under half circle shape mode, the menu will enlarge touch area.

Bug: 173958541
Test: atest AccessibilityFloatingMenuTest AccessibilityFloatingMenuViewTest AccessibilityTargetAdapterTest
Change-Id: Iec53ef71d7e0abe5c7619d4e5f67862ca56dfd1f