Ignore react 421 errors

[lforst]

These errors are not actionable because they do not contain a stack trace or information about locality. We should ignore them.

Comment raising this: #6295 (comment)

[enjoyjeremy-bc]

Hi, I'm also interested in the ability to filter out these unactionable errors. A website I manage is experiencing about 125k of these errors per day. Can this be prioritized?

[andreiborza]

Hello, we are currently on a company-wide hackweek and thus on limited support. We'll look at this next week.

[lforst]

@enjoyjeremy-bc looking at this issue again I am not sure whether we should ignore it out of the box because it indeed highlights an issue with your application.

If you want to ignore the error for your project, you can add it to the ignoreErrors list like I suggested here: #6295 (comment)