[Bug][PIP-379] Hash ranges should not move from one consumer to another when a consumer joins

[lhotari]

          > What happens if a hash is moved between existing consumers? Is it handled?

Yes. All removed ranges are processed in both when a consumer is added and when it's removed. In some experimental testing I noticed that it actually could happen also when a consumer is added, due to how hash range conflicts are resolved. There's a need to make an improvement that when there are conflicts that the first assigned consumer is preserved instead of replacing it. I'll make a PR for that since hash range conflicts are fairly likely to happen with the reduced hash range of 65535 and 100 hash points when there's a large amount of consumers. I'll address that.

Originally posted by @lhotari in #23352 (comment)