Remove unused Ruby client reply helpers

[kpumuk]

This is a follow-up to #3345. I left the old helpers around, so that code generated with the compiler pre- and post- seqid change would work (although pre- would not generate correct sequence IDs nor validate them).

With this cleanup we force people to re-generate, as per Ruby documentation on version upgrade. This will also go into the next release (0.24.0), so I feel like it should not affect anybody.

• Did you create an Apache Jira ticket? (Request account here, not required for trivial changes)
• If a ticket exists: Does your pull request title follow the pattern "THRIFT-NNNN: describe my issue"?
• Did you squash your changes to a single commit? (not required, but preferred)
• Did you do your best to avoid breaking changes? If one was needed, did you label the Jira ticket with "Breaking-Change"?
• If your change does not involve any code, include [skip ci] anywhere in the commit message to free up build resources.

[kpumuk]

@Jens-G this is somewhat a lower risk PR, do you mind if I merge it to practice? I was looking at https://thrift.apache.org/docs/committers/HowToCommit.html and it seem kind of outdated. Thinking about something like

gh api -H "Accept: application/vnd.github.v3.patch" repos/:owner/:repo/pulls/3395 | git am --ignore-space-change
 
git log --format=fuller -n1
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
commit 77151745bac95752cf2d745215c7639ffcd114a5 (HEAD -> master)
Author:     Dmytro Shteflyuk <kpumuk@apache.org>
AuthorDate: Thu Apr 16 22:24:48 2026 -0400
Commit:     Dmytro Shteflyuk <kpumuk@apache.org>
CommitDate: Thu Apr 16 23:40:35 2026 -0400

    Remove unused Ruby client reply helpers

Output seems to match (somewhat) what you have been doing. Would probably add Client as well, not quite sure how Patch is relevant given Author is preserved as is.