Add a filegroup to allow exporting the kotlinx-coroutines-play-services src files am: 7687439cf5 am: 0807063f08 am: df9b2d2e78 am: 49fa8fcd45

Original change: https://android-review.googlesource.com/c/platform/external/kotlinx.coroutines/+/2064527

Change-Id: I3ea7cd9c666d7af1f62ab292a278f1fdd4146d07
Signed-off-by: Automerger Merge Worker <[email protected]>