Gecko sync update (#7335)

Co-authored-by: Kyle Ju <[email protected]>

Author: moz-wptsync-bot

css/css-mixins/META.yml

@@ -199,6 +199,11 @@ links:
   - subtest: Function in a cycle with its own default
     test: dashed-function-cycles.tentative.html
   url: https://bugzilla.mozilla.org/show_bug.cgi?id=1950126
+- product: firefox
+  results:
+  - subtest: Can query named container in shadow
+    test: function-shadow-container.html
+  url: https://bugzilla.mozilla.org/show_bug.cgi?id=1950667
 - product: firefox
   results:
   - subtest: Basic @container