Use SettingsShim to hide different implementation in shim

TetheringService call different Settings API to check write settings
permission between R and S.

Bug: 182211575
Test: install S module to R device and both run mts tests build with S
and R.

Change-Id: I3e7f6525e9776992bd96b17c132b749b12285bbd
Merged-In: I3e7f6525e9776992bd96b17c132b749b12285bbd
2 files changed