Faster LE Audio device pairing

LE Audio related profiles take long time to connect. Most of this time
is spent waiting on GATT operations waiting to be sent / received.

Currently, we use high connection parameters just for service discovery,
and relax them immediately after that.

After this patch, we would use high speed connection parameters once we
find device might be LE Audio capable. The parameters are relaxed after
LE Audio profile is connected. In case LE Audio is disabled, we start a
timer that would disable parameters 15 seconds after service discovery
is finished.

Test: Bond wiht LE Audio capable device, note profile connection time
      reduction.
Bug: 319405267
Bug: 296836982
Change-Id: Id238ca459333e82581cf71952ce8abc9a2b8aafe