Framework: Allow root to send bg-dexopt

To allow testing, and work on rooted userdebug devices, allow the root
user to issue package bg-dexopt commands.

Bug: 111798412
Exempt-From-Owner-Approval: cherry-pick
Test: atest BackgroundDexOptServiceIntegrationTests
Merged-In: I5f52b8322ba386c797a9176a1b216cc547c66456
Change-Id: I5f52b8322ba386c797a9176a1b216cc547c66456