[Fixes #11349] Keep into account maplayers visibility and order when …

[mattiagiupponi]

…generating map thumbnails

ref #11349

Checklist

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[codecov]

Codecov Report

Merging #11443 (e00704c) into master (006332b) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #11443   +/-   ##
=======================================
  Coverage   61.95%   61.95%           
=======================================
  Files         867      867           
  Lines       51577    51577           
  Branches     6467     6467           
=======================================
+ Hits        31954    31956    +2     
+ Misses      18084    18081    -3     
- Partials     1539     1540    +1