use miniforge3 for our docker builds instead of mambaforge

[valeriupredoi]

Description

Missed this in #2556 - this is the last but on Mambaforge apart from the RTD wait

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.01%. Comparing base (e69ec5d) to head (decd828).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2558   +/-   ##
=======================================
  Coverage   95.01%   95.01%           
=======================================
  Files         251      251           
  Lines       14268    14268           
=======================================
  Hits        13557    13557           
  Misses        711      711           

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[bettina-gier]

beep-boop your seal of approval has surfaced from the waters. It has grepped the Core as well to see that there are no more mambaforge fishes to catch other than the readthedocs which requires external support first.

[valeriupredoi]

many thanks, Seal Of Approval 🦭