Properly store CustomTile added/removed

We use UserFileProvider to properly persist CustomTile that are
added/removed for secondary users, so they'll get the proper
onTileAdded/onTileRemoved message.

Test: atest com.android.systemui.qs
Test: look at filesystem
Fixes: 180126509
Change-Id: I966312e017288f69b2fc680b464a7ef3bb6c0c92
6 files changed