l2cap: Allow services without config indicator cb to register am: f305697c...

l2cap: Allow services without config indicator cb to register am: f305697c am: c8324485 am: 4ccf83b0 am: 4452f659

Original change: https://android-review.googlesource.com/c/platform/system/bt/+/1497502

Change-Id: I988dc3b95e34714b9979925312232be76d520119