feat(#AlwaysOnMagnifier): Adjust FullScreenMagnificationGestureHandler to support always on feature

For b/267210808, we adjust the gesture handler to disable the magnification after user zoomInTemporary by shortcut and release. It's the original behavior. After the feature AlwaysOnMagnification is supported in FullScreenMagnificationController, if the feature is enabled, the gesture handler will make magnifier zoom to 100% and keep activated instead.

Besides, in FullScreenMagnificationGestureHandlerTest, we rename STATE_ZOOMED to STATE_ACTIVATED. It is becasue user can activate the magnifier and zoom to 100%.

Bug: 267210808
Test: manually
      atest FullScreenMagnificationGestureHandlerTest
Change-Id: I44e6c54fbdec02562f7f6bfca3ab054db4ed5db5