RootCanal: Delay the first ACL packet sent on a connection

The PTS test L2CAP/CMC/BV-13-C's flakiness is caused by the PTS tool
handling a received ACL packet before the connection complete event
when it is received too early after the connection establishment.

This change adds a delay of 100ms to the first ACL packet being
sent to work around this issue.

Bug: 275294283
Test: atest pts-bot:L2CAP/CMC/BV-13-C
Change-Id: If32e40f4ef13f948791719fc813ae3aebd6e61aa