Batch page progress bar triggers a HTTP protocol compliance failed in F5 WAF

Looks like there was a CI failure.

Fixed CCF for #8.

Not sure how to test this but 100% seems like a feature that would need a test case.

While the batch process in our client's Drupal site is still running great with the provided patch, I think the F5 WAF has it wrong:

- RFC2616 says a Content-Length >= 0 is valid: https://datatracker.ietf.org/doc/html/rfc2616#section-14.13, and t
- The F5 docs states that this behavior differs from what the RFC says: https://my.f5.com/manage/s/article/K10280: "Note: While RFC 2616 section 14.13 states that Content-Length can be equal to or greater than zero, the BIG-IP ASM considers a value of zero to be a violation."

Although adding this patch to drupal core would save me some lines in my composer.json file, in hindsight I think this change should not be added to Drupal core, as it clearly is a 'misinterpretation' of the RFC by the F5 waf, and polluting the drupal core codebase with exceptions for every piece of software out there should not be the way to go.

So I think this issue should be marked as Closed/won't fix.

If someone needs it, here is a patch which works for 10.x