Use resources for pairing ui package

The pairing package is set to "com.android.settings" which means
overlays can't change the package that's responsible for UI interaction
when pairing and access request events happen.  Move it to a resource.

Test: pair a device, initiate pair from remote
Change-Id: I5731bcdcfed58b72b4e15e3e60035c7e8144b7d4
Bug: 35163738
Fix: 35219650