Incoming HF connection: CB interaction between BTA <-> BTIF

For incoming connections we are not storing the handles in BTIF which
implies that BTIF ignores the message (and so does jni -> java). This is
fixed by sending the handle as part of BTA message on incoming accept.

Other bugs include connection from remote (incoming) and disconnecting
from host. They also depended on not storing the handle properly in
first place.

Bug: b/33555377
Bug: b/30984220

Test: Manual testing of incoming connections
Change-Id: I84950d42aba2d2c975ea86cc8217fd0129cc90e9