Fix permissions xml and provider access

ThemePicker need to add its use of permissions and declare the
priv app permission parts in an xml file to be able to start.

ThemePicker also need to declare which other apps it intends to
interact with in queries. This enables the Launcher grid/icon preview.

Test: Manual
Bug: 274634330
Change-Id: I55fb94279abeab15dd16a6cabc0bf086c621fc42