Remove readability refactor for failover auth to fix clang warning

[madolson]

As part of #1463, I made a small refactor between the PR and the daily test I submitted to try to improve readability by adding a function to abstract the extraction of the message types. However, that change apparently caused GCC to throw another warning, so reverting the abstraction on just one line.

https://github.com/madolson/valkey/actions/runs/12472455780

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.82%. Comparing base (d00c856) to head (53c542d).
Report is 1 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1481      +/-   ##
============================================
- Coverage     70.86%   70.82%   -0.05%     
============================================
  Files           119      119              
  Lines         64852    64852              
============================================
- Hits          45958    45930      -28     
- Misses        18894    18922      +28     

Files with missing lines	Coverage Δ
src/cluster_legacy.c	86.79% <100.00%> (-0.07%)	⬇️

... and 11 files with indirect coverage changes