Move videoqualityfloor test assets to dl.google.com

Have the test pull the test assets from production dl.google.com instead of
experimental buckets on storage.googleapis.com

Bug: 406491814
Flag: TEST_ONLY
Test: atest CtsVideoQualityFloorHostTestCases
Change-Id: Ib1b5de4267f185697ed3b5b43b474093c251f29b