@AltamashShaikh I think the TagManager submodule reference might need updating in this PR?

I got this error when loading the no-data react tab:

Too few arguments to function Piwik\Plugins\TagManager\TagManager::embedReactTagManagerTrackingCode(), 
1 passed and exactly 3 expected
in /var/www/matomo/plugins/TagManager/TagManager.php line 271

The same error is shown on the UI tests. Running git submodule update after checking out this branch results in a detached head for the TagManager submodule. Checking out the TagManager 4.x-dev branch fixed the issue for me locally.

You probably need to do something like:

cd [matomo folder]
git checkout cherrypick-react-and-js-cleanup
cd plugins/TagManager
git checkout 4.x-dev
cd ../..
git add plugins/TagManager
git commit -m "Update submodule"
git push

Which should update this PR to reference the 4.x-dev branch for TagManager and fix the UI test.

@bx80 updated submodule as suggested

@sgiehl @bx80 are we good to merge this ?