Add method for setting whether emergency gesture UI is showing

This ContentProvider method will be called by the safety client app

Bug: 256494850
Test: manual
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:78b6eb440c8ed4ae7e3c1916172a8d5e074ceb50)
Merged-In: Id7f6480ca4b973b34801033ccf5d010eae2dfc12
Change-Id: Id7f6480ca4b973b34801033ccf5d010eae2dfc12