Submit feedback within Firefox still not function
The option in the Help menu for "submit feedback" is still present on version 87 but is no longer functional and has been out of service for 3 months.
Is an expected date or version pending to reactivate or will it be removed?
As for your question about is the "submit feedback", it is still ongoing, the only you need to do is to update your Firefox version to the latest which is 89.0.1 and you will be able to see the submit feedback form works normally. Unfortunately, the "Submit Link" seems to be redirected to the wrong URL, what I suggest is to use another platform to submit your feedback. You can go through the URL in the comment section to submit your feedback to Firefox
Hope my answer can help solve your problem