Merge pull request #5169 from Unity-Technologies/fix-link-check-forums

exclude forum links

markdown-link-check.full.json

             "comment": "Allow future release tags"
         },
         {
-            "pattern": "https://forum.unity.com/forums/ml-agents.453/",
-            "comment": "Not reachable from github action"
+            "pattern": "https://forum.unity.com/",
+            "comment": "Returns 307 (temporary redirect) which causes link check to fail."
         },
         {
             "pattern": "mailto:",