OnCommittedResponseWrapper does not track "Content-Length" in all cases

[balrok]

Describe the bug
Recently a Bug in spring-security surfaced, where it was found that the OnCommittedResponseWrapper does not correctly track the content-length, if it was set by setHeader, setIntHeader, addIntHeader.

See here for the fix: spring-projects/spring-security#18798

The spring-session-project also includes an OnCommittedResponseWrapper, which looks identical to that of spring-security. Therefore the fix must be applied here too.

To Reproduce
Use spring-framework 7.0.5 because the header-optimizations of spring-projects/spring-framework#36334 will not use addHeader for Content-Length anymore.
Or set the content-length manually with any method other than addHeader (i.e. setHeader, setIntHeader, addIntHeader).

Expected behavior
The "Content-Length" is tracked for all method-calls.