PTS-bot: Build AudioTrack at first Start

- Prevent a server crash when the audioFlinger could not create
the track. If so, the server now respond with a gRPC error instead of
crashing the whole server.

- Apply ktfmt

Test: atest pts-bot --iterations=10

Change-Id: I4b93e6a209c6851bea693b89e48a9c58c6b98d9e