MM-52165 : Remove 50% maxWorker on Channels test run (#22962)

* test

* remove boards maxWorkers

---------

Co-authored-by: Caleb Roseland <caleb@calebroseland.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/package.json

@@ -20,6 +20,7 @@
     "blessed": "0.1.81",
     "chalk": "4.1.2",
     "concurrently": "7.6.0",
+    "cross-env": "7.0.3",
     "eslint": "8.37.0",
     "strip-ansi": "6.0.1"
   },