[Panlingual] Clear per-app locales setting when the LocaleConfig is

removed

When a user has set per-app locales for a specific application from the system locale selector, and then the LocaleConfig of that application is removed after apps upgraded, the per-app locales needs to be reset to system default locales to avoid the user being unable to change the system locales.

Bug: 234131462
Test: 1.Run some CTS and unit test cases.
      2.Manual test.
Change-Id: I2809206ae31a745d297128f9e496023c4d670e11