remove unused StripGreasedVersions function

[marten-seemann]

Such a function would defeat the purpose of greasing. Fortunately, we didn't actually use it anywhere.

[codecov]

Codecov Report

Merging #3214 (9520f24) into master (e9d12b7) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3214   +/-   ##
=======================================
  Coverage   85.40%   85.41%           
=======================================
  Files         134      134           
  Lines        9825     9821    -4     
=======================================
- Hits         8391     8388    -3     
+ Misses       1060     1059    -1     
  Partials      374      374           

Impacted Files	Coverage Δ
internal/protocol/version.go	95.00% <ø> (-0.45%)	⬇️
internal/utils/rand.go	75.00% <0.00%> (+12.50%)	⬆️

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