(1/n) Remove usage of isKeyGestureSupported() from KeyGestureController

isKeyGestureSupported is synchronous API that makes system server
dependent on handler and can cause ANR if handlers misbehave.
It was added as a stop gap for multi-key gestures that require
some SysUI info like keyguard state, display state, etc, to decide
if the key needs to be consumed or not at the start of the gesture.

With this refactor:
- Use Display state for Default display as a replacement for
mDefaultDisplayPolicy.isAwake() which was added initially to ensure
the shortcut chords are only trigerred if default display is on.

In subsequent CLs:
- WM policy added an API to check isKeyguardLocked() and we will
use that for checking keyguard status
- Move A11yShortcutController to KGC to circumvent the need of the
isShortcutAvailable() API

Test: atest KeyGestureControllerTests
Bug: 358569822
Bug: 383602794
Flag: EXEMPT refactor
Change-Id: I000c6a46ae0e17495db5fa5f0f039940549bc243