Limit branch names on GitHub PR's to 255 bytes

[jeffwidman]

Is there an existing issue for this?

• I have searched the existing issues

Code improvement description

Our internal error logs are showing a PR branch failed to be created because the branch name it was trying to create was 299 characters.

According to the reporter, the limit for GitHub branch names is 255 (244 really after refs/heads).

We should be able to leverage the great work @TomNaessens did in #5338 to to enforce the proper character limit on GitHub.

[jeffwidman]

Looks like the limit may be enforced on bytes, not characters: https://stackoverflow.com/a/66514473/770425

I googled but couldn't find any public docs published by GitHub documenting the limit.

Since #5338 hasn't made it to a public release yet we may want to teak the option slightly to enforce bytes limits rather than characters... or we could keep it sane for humans and just enforce a slightly smaller character limit such that it's unlikely to ever go over the bytes limit.