When a Media3 controller calls play on a Media3 session, the call
is currently not routed through the platform session at all.
This means the usual exemption to start a FGS for media controller
interactions is not triggered.
We can manually ensure this exemption is given by sending a custom
platform command to the session. The Media3 session will never
receive this command as it's not a known Media3 custom command.
Sessions will see a single onConnect call with a platform controller
from the sender app though. We can prevent this on newer versions of
the code by dropping the onCommand call early.
PiperOrigin-RevId: 679115247
f4eef88089