UTM removal is broken for React pages

[escattone]

Summary
The GA hitCallback function on the ga('send', 'pageview', ...) call, which removes the UTM query parameters in the loaded URL, is broken for React pages.

Steps To Reproduce (STR)
Go to https://developer.mozilla.org/en-US/docs/Web/HTML?utm_xxx

Actual behavior
After the page loads, the URL remains https://developer.mozilla.org/en-US/docs/Web/HTML?utm_xxx

Expected behavior
After the page loads, the URL should be adjusted to https://developer.mozilla.org/en-US/docs/Web/HTML (the utm_* query parameter should have been removed).

Additional context
You can observe the correct behavior if you try https://wiki.developer.mozilla.org/en-US/docs/Web/HTML?utm_xxx

[escattone]

This discovery arose from the work on #5986.