Bug 1891023 - Clear CallbackObject's JS references when refcnt drops to 0, r=mccr8

See also https://searchfox.org/mozilla-central/rev/058ab60e5020d7c5c98cf82d298aa84626e0cd79/xpcom/base/CycleCollectedJSContext.cpp#213-218 for another similar-ish Reset() call.

Differential Revision: https://phabricator.services.mozilla.com/D207273

dom/bindings/CallbackObject.cpp

@@ -29,7 +29,7 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CallbackObject)
 NS_INTERFACE_MAP_END
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(CallbackObject)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(CallbackObject)
+NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE(CallbackObject, Reset())
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(CallbackObject)