Remove libbinder_rpc_unstable from system required libs

libbinder_rpc_unstable is in the list of system required libs, but the
library is already located in the system/{LIB}, and this creates link to
the self namespace. Remove libbinder_rpc_unstable from system required
libs as it doesn't make sense to have require and provide same library
in a single image.

Bug: 298333253
Test: Cuttlefish build and boot succeded
Change-Id: Idb40e1dbc1053d4882093c188a36b2cc8d86e918