Release virtual display before stopping projection

As described in b/140399127, if the media projection is stopped first,
the virtual display will not get released. So we need to release the
display first and stop projection after that.

Bug: 174800535
Test: 'Recording Display' no longer appears in dumpsys after ending a screen recording
Change-Id: I8775068677b3ea5d0836a64579b0539e2e1aafae