Fix issue with Rainbow scaler for list-inputs

[hombit]

Fixes #492

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.06%. Comparing base (c0d1a6e) to head (d533c63).
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #493   +/-   ##
=======================================
  Coverage   82.06%   82.06%           
=======================================
  Files           9        9           
  Lines        2570     2570           
=======================================
  Hits         2109     2109           
  Misses        461      461           

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[codspeed-hq]

CodSpeed Performance Report

Merging #493 will not alter performance

_{Comparing fix-scaler-list-input (d533c63) with master (c0d1a6e)}

Summary

✅ 104 untouched benchmarks