LE Audio: force GATT over LE finish before returning services

When doing service discovery, we would first trigger SDP, then LE on
GATT transport.
If we are dealing with LE Audio and A2DP capable device, ensure all
services are discovered before passing services to Java.
If we return just SDP first, we might start expensive profile
connections, that would later need to be torn down when LE Audio profile
connect

Test: pair with LE Audio capable dual mode device
Bug: 248340112
Change-Id: I32394168eebd91e39db5157a5d6edc8c26ba9229