Y26-204 - Remove MySQL 8.0 references

[BenTopping]

Relates to sanger/General-Backlog-Items#738

Changes proposed in this pull request

• Removes mysql 8.0 from CI matrices

Extension of work from #5702

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.93%. Comparing base (2d9ac52) to head (eab757a).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5965      +/-   ##
===========================================
- Coverage    84.97%   84.93%   -0.05%     
===========================================
  Files         1496     1496              
  Lines        33968    33968              
  Branches      3622     3622              
===========================================
- Hits         28865    28850      -15     
- Misses        4255     4271      +16     
+ Partials       848      847       -1     

Flag	Coverage Δ
javascript	76.31% <ø> (ø)
ruby	84.81% <ø> (-0.03%)	⬇️

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