[Settings] Avoid access Controller from Slice

AirplaneModePreferenceController is designed to be run in UI thread.
However, MobileDataSlice is designed to be run in SliceProvider.

Accessing AirplaneModePreferenceController within SliceProvider which
create a possibility of crash.

Bug: 145689275
Test: manual
Change-Id: Ic9eee407917a94c7247feb3afc709d4642cd9900
1 file changed