This commit simplifies the HTTP compression configuration for Reactor
Netty servers.
Also, this commit removes a test for the
`server.compression.min-response-size` support, as this is only
supported when the HTTP response contains a `Content-Length` header.
Since most Spring WebFlux responses are using
`Transfer-Encoding: chunked`, we should not test for that case.
See gh-12268
438004efe5