PTS-bot: fix AVDTP/SRC/INT/SIG/SMG/BV-17-C

Add a delay between BluetoothA2dp.STATE_CONNECTED and
audiotrack.play() because sometimes the AVDTP start request
is never sent.

Bug: 234891800
Bug: 241962982
Test: atest pts-bot:AVDTP/SRC/INT/SIG/SMG/BV-17-C -v --iterations=30
Ignore-AOSP-First: Cherry-picked from AOSP
Merged-In: Ie5d28789acff428d99a78f67c6a933dc3c142b28
Change-Id: Ie5d28789acff428d99a78f67c6a933dc3c142b28