Delegate PrintServicesLoader to the framework's one

1. Remove the duplicated PrintServicesLoader in Settings
2. Make a androidx.loader in Settings and internally just delegate all calls to the real PrintServicesLoader
3. Get the result from the real loader

Test: manual
Fixes: 111581651
Change-Id: I2a9b3653f5c68f8383a468cd16ef5f7c3fd4bc3a