Pass BIP client status down and use it to decide to send image handles

The new avrcp architecture has the design such that all requests to Java
are agnostic of which device is asking for them. However, image handles
are not meant to be sent if there is no BIP connection with that device.

Rather than invalidate the previous design assumption, this patch sends
that status down to the connection handler and device objects to use
when building response packets. The image handles, if included, will be
automatically removed if there is no client connection. If no image
handles are sent, none will be included.

Tag: #feature
Bug: 153076316
Test: Build, flash, make sure existing metadata isn't impacted and is
still sent when requested. Make sure imge handles are sent, when they
exist, if and only if we've connected a client on the Java side BIP OBEX
server.

Change-Id: If252abe120188df2bcdabed22382fba070d17f32