Camera: fix race issue in Camera2 clients

Updating of the mDevice sp<> is racy.
This change will cause the Camera3Device object lives until
the client is destructed (which can be a few seconds after
camera app closed and GC kicking in to delete the client)
The benefit is the dumpDevice can remain lock free.

Also fix a problem where we call virtual function disconnect in
Camera3Device destructor.

Test: the double free problem cannot reproduce
Bug: 112639939
Change-Id: I77762db8f59cf33891631d13fc3bdb3830ae08fb