[16.1.x] [#16899] Update ConnectionMetadata protocol version on every Hot Rod request - #17329

Backport: #17235

Closes: #16899

ConnectionMetadata.protocolVersion was only updated during PING processing in CacheRequestProcessor.pingResults(). Since auto-negotiating clients send the initial PING at the safe handshake version (3.1), the metadata permanently showed HOTROD/3.1 even after the client upgraded to 4.1 for all subsequent requests.

This PR moves the protocolVersion update into the hotrod.gr grammar's root request rule, so it runs after every request's header is parsed. The redundant update in CacheRequestProcessor.pingResults() is removed along with unused fields in HotRodVersion, HotRodHeader, and ProtocolVersion.

Author Checklist (all must be checked):

• Commit message includes a reference to the corresponding GitHub issue (e.g. commit message: "[#00000] Issue title...") and is formatted according to our git message template.
• Commits have been squashed into self-contained units of work (e.g. 'WIP'- and 'Implements feedback'-style messages have been removed).
• The PR includes new/modified unit and integration tests that exercise the changes. Include additional manual testing instructions if necessary. If the PR does not include tests, clear justification MUST be provided.
• The PR includes new/modified documentation. If the PR does not require documentation changes, clear justification MUST be provided.
  • No documentation changes needed: internal behavior fix with no user-facing API change.
• Log messages of level INFO and above have been internationalized.
• If the PR affects performance, include before/after benchmarks.
  • No performance impact: the ConnectionMetadata.protocolVersion() setter is a simple field assignment.
• If the PR affects output (such as logs, CLI, Console), provide an example (text snippet/screenshot).
• If the PR requires a followup or is part of a larger body of work, ensure that relevant GitHub issues have been created to track the additional work.