test: reset Current.user before each example (#8126)

Co-authored-by: Sojan Jose <sojan@pepalo.com>

spec/listeners/action_cable_listener_spec.rb

@@ -9,6 +9,8 @@ describe ActionCableListener do
 
   before do
     create(:inbox_member, inbox: inbox, user: agent)
+    Current.user = nil
+    Current.account = nil
   end
 
   describe '#message_created' do