has_client: Improve subscribtion to control point

As per specification we should register for notification when EATT is
used and indication if EATT is NOT used. This is bit odd as having
support and being able to connect, and maintaing connection are
different things.
To be on the save side we would like to register to both - notification
and indication and let server to decide what it is sent (based on the
bearer).

With this patch, we register to anything what servers allow dispite
EATT tracking.

This will also help PTS testing

Bug: 238171211
Test: atest BluetoothInstrumentationTests
Test: PTS
Tag: #feature
Change-Id: I7c30278de00e3e75c6ecd9b6c55258b7eef92fe9