Fix memory leak in shade service list dialog

RecyclerView adapters hold reference to RVs they were added in. Since we
reuse the adapter, we leak the whole RV view hiearchy on every dialog
open. Clear the adapter on dialog close which also clears the references
in RV#setAdapterInternal.

Bug: 424097770
Test: tested on Panther, ran tests
Flag: EXEMPT bugfix
Change-Id: I124fe6a333c7bb4a63cb06592faa08814562316e