Auto merge of #12623 - notriddle:master, r=emilio

Complete animations whether or not cascade needs done

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #12554 (github issue number if applicable).
- [x] There are tests for these changes

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tests/wpt/mozilla/meta/MANIFEST.json

@@ -6150,6 +6150,12 @@
             "url": "/_mozilla/css/animations/basic-linear-width.html"
           }
         ],
+        "css/animations/basic-transition.html": [
+          {
+            "path": "css/animations/basic-transition.html",
+            "url": "/_mozilla/css/animations/basic-transition.html"
+          }
+        ],
         "css/empty-keyframes.html": [
           {
             "path": "css/empty-keyframes.html",