Better error message for hv.Cycle if wrong backend

[hoxbro]

Fixes #5238 https://discourse.holoviz.org/t/no-colormaps-in-hv-cycle/4048

[codecov-commenter]

Codecov Report

Merging #5379 (6c0faf4) into master (67f1fcf) will decrease coverage by 0.00%. The diff coverage is 20.00%.

@@            Coverage Diff             @@
##           master    #5379      +/-   ##
==========================================
- Coverage   88.07%   88.06%   -0.01%     
==========================================
  Files         301      301              
  Lines       61965    61969       +4     
==========================================
  Hits        54575    54575              
- Misses       7390     7394       +4     

Impacted Files	Coverage Δ
holoviews/core/options.py	82.44% <20.00%> (-0.36%)	:arrow_down:

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