Automotive builds can come without a file picker. In such cases, the
RingtonePickerActivity shouldn't need to show the "Add New Ringtone"
list item.
Bug: 138454052
Test: manual
Change-Id: Iceb5555493420898d6eafe79e3299d5bd3a77a98
Some OEMs have requested the ability to customize the ringtone
picker logic, and that's already supported by the existing
"config_defaultRingtonePickerEnabled" parameter today.
This change is a clean refactoring of the AOSP ringtone picker out
of MediaProvider and into a new "SoundPicker" module, which is
consistent with how some OEMs have already defined their own
"SoundPickerPrebuilt" module.
Bug: 134542205
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: Iadc60e731e6dcfce651f89bc7598e65541ab0ddf
