Fix TileServiceTest for new tiles

There was a fault where TileServiceTest would mistake old
start/stopListening logs for signals that the TestTileService has
processed quicksettings open/collapse. This was particularly problmatic
for testSetPendingIntentPersistsAfterShadeIsClosed where the tests
needed to open close and then open the quicksettings.

We fix that problem by simply clearing the old logcats.

FLAG: EXEMPT TEST ONLY
Bug: 371556874
Test: atest android.host.systemui.TileServiceTest
Change-Id: I007cea36bb48b7cf3412f65c23bfa88ab5cd4856