[Action Corner] Action of the same action corner state should not be...

[Action Corner] Action of the same action corner state should not be re-triggered after unlocking screen

Issue:
1. User moves cursor to an action corner, triggers an action. For example, the action is lockscreen.
2. Screen is locked, cursor does not move, user unlocks the screen.
3. Because the cursor is still in the same active corner, once the screen is unlocked and action corner state is re-subscribed, it thinks it is a new action corner and triggers lockscreen again.

The action corner state is already handled before locking screen, it should be ignored until the cursor leaves the action corner and re-enter it.

This CL adds distinctUntilChanged to make sure we only trigger action when the state is unhandled.

Bug: 436184783
Test: ActionCornerInteractorTest
Flag: com.android.systemui.shared.cursor_hot_corner

Change-Id: I3314803ae0a9d74aced7c51f3f37e2c7d0269df9