AVCRP Controller support Get Item Attributes

Add support for the GetItemAttributes command when the browsing chanel
is connected.

Bug: 149411071
Test: Play a song from a paired phone compare metadata and HCI logs.
Change-Id: I0ac3c3bb7c9d1c3c72f0e2bad13d276c836ecf6f
Merged-In: I0ac3c3bb7c9d1c3c72f0e2bad13d276c836ecf6f