Fix device config writes in TranscodeTest for U

Starting in U, adb can't write to DeviceConfig. This is leading to
unsuccesful writes and eventually test failures in TranscodeTest where
we're attempting to write to DeviceConfig using UiAutomation
executeShellCommand.

To fix these failures, we're instead adopting the shell permission
identity to write device config using the DeviceConfig APIs.

Test: atest TranscodeTest
Bug: 270825056
Change-Id: Iaf98b7e20bd48fd92adcb94b44387437803fbef9
1 file changed