Firefox 144 adds RTCDataChannel closing event (#27931)

FF144 RTCDataChannel closing event

Author: hamishwillee

api/RTCDataChannel.json

@@ -353,7 +353,7 @@
             "chrome_android": "mirror",
             "edge": "mirror",
             "firefox": {
-              "version_added": false
+              "version_added": "144"
             },
             "firefox_android": "mirror",
             "oculus": "mirror",