recovery: Add ability to interrupt UI

Normally calling a UI method will block
indefinitely until the UI is actually
used. This creates a method to interrupt
the UI, causing waitKey to return -2. This
in turn, will cause ShowMenu to return -2.
This allows switching between recovery and
fastbootd via usb commands.

Test: adb shell /data/nativetest64/recovery_unit_test/recovery_unit_test
Bug: 78793464
Change-Id: I4c6c9aa18d79070877841a5c9818acf723fa6096