Fix versioned message json deserialization

[jstarry]

Problem

Versioned message deserialization is broken when using serde_json because serde_json expects the versioned message visitor to handle a u64 rather than a u8.

Summary of Changes

• Update the message prefix visitor to implement visit_u64 instead of visit_u8
• Add tests

Fixes #34608

[mergify]

Backports to the beta branch are to be avoided unless absolutely necessary for fixing bugs, security issues, and perf regressions. Changes intended for backport should be structured such that a minimum effective diff can be committed separately from any refactoring, plumbing, cleanup, etc that are not strictly necessary to achieve the goal. Any of the latter should go only into master and ride the normal stabilization schedule. Exceptions include CI/metrics changes, CLI improvements and documentation updates on a case by case basis.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (711215f) 81.8% compared to head (49fbd7d) 81.8%.
Report is 7 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #34808     +/-   ##
=========================================
- Coverage    81.8%    81.8%   -0.1%     
=========================================
  Files         825      825             
  Lines      223124   223129      +5     
=========================================
- Hits       182525   182523      -2     
- Misses      40599    40606      +7     

[semgoSE]

We are looking forward to it