Use updated flag.

Link to the main TARE flag and default value instead of the Settings
default.

Bug: 158300259
Test: atest CtsAlarmManagerTestCases
Test: atest CtsBatterySavingTestCases
Test: atest CtsJobSchedulerTestCases
Test: atest SettingsBackupTest
Test: atest frameworks/base/services/tests/mockingservicestests/src/com/android/server/alarm
Test: atest frameworks/base/services/tests/mockingservicestests/src/com/android/server/job
Test: atest frameworks/base/services/tests/mockingservicestests/src/com/android/server/tare
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/job
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/tare
Test: Interact with UI and check settings via adb
Change-Id: I6afd0bdf56f39758076b6182fc4893a37760428b