Run tests for all web app packages in CI (#22579)

* Run tests for all web app packages in CI

* Test specific packages instead of all of them

* Revert back to using test-ci scripts and rely on Jest to count the number of CPU cores

* Revert more changes made to the web app CI tests

* Fix path to client package tests

webapp/channels/package.json

@@ -224,7 +224,7 @@
     "run": "webpack --progress --watch",
     "dev-server": "webpack serve --mode development",
     "test": "cross-env TZ=Etc/UTC jest --maxWorkers=50%",
-    "test-ci": "cross-env NODE_OPTIONS=--max_old_space_size=5120 TZ=Etc/UTC jest --ci",
+    "test-ci": "cross-env TZ=Etc/UTC jest --ci --maxWorkers=100%",
     "clean": "rm -rf dist node_modules .eslintcache .stylelintcache tsconfig.tsbuildinfo",
     "stats": "cross-env NODE_ENV=production webpack --profile --json > webpack_stats.json",
     "updatesnapshot": "cross-env TZ=Etc/UTC jest --updateSnapshot",