Update WebDriver BiDi data (#29345)

Author: mdn-bot

webdriver/bidi/browser.json

@@ -174,7 +174,8 @@
                 "chrome_android": "mirror",
                 "edge": "mirror",
                 "firefox": {
-                  "version_added": false
+                  "version_added": false,
+                  "impl_url": "https://bugzil.la/1975279"
                 },
                 "firefox_android": "mirror",
                 "oculus": "mirror",