Migrate Shell app to use the new bugreport API.

Add new calls to bugreport API, all the while keeping the previous code
and logic untouched.

Added feature flag in Settings which if untouched, runs the old dumpstate workflow
by default. To test the new workflow turn on the feature flag from UI or
`adb shell setprop settings_call_bugreport_api true`.

Add permission TRIGGER_SHELL_BUGREPORT so that not all can send
broadcasts to trigger bugreports.

Create new receiver BugreportRequestedReceiver for the new broadcast intent that the shell app will
use.

Whitelist Shell app to use the bugreport API.

Bug: 123617758

Test: manually built and flash to device. Turn on the feature flag, generate bugreports and check
the onProgress and onFinish notifications.
Test: Turn off the feature flag test old workflow.

Change-Id: I1c7c258a48815a0386d7d4771301cd76f9cae3d0