[Misc] Move MediaProjectionManagerRepository to a more broad location.

The status bar screen sharing chips feature (b/332662551) needs the
media projection info just like the media task swithcer does, so this
CL moves the repository out of the `mediaprojection.taskswitcher`
package and into just `mediaprojection`.

A future CL will re-use this repository for the new status bar chip.

Bug: 332662551
Test: atest MediaProjectionManagerRepositoryTest
Flag: com.android.systemui.pss_task_switcher
Change-Id: Ia170c7153f75a6e036a86eec228e7924c964dd32