Prevent non-system ShutdownActivity from being launched by BatteryService

Bug: 380885270
Test: adb shell dumpsys battery set temp 1001
Flag: EXEMPT bug fix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:8cda6fda96c420588a5f8f5112522cfde14659b4)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:d21c4b723f465dc887eb942d93fc06f750a24678)
Merged-In: I6c00b47d424d81712bd9634c31de4b7d2e9cbe31
Change-Id: I6c00b47d424d81712bd9634c31de4b7d2e9cbe31