[8.0] fix: from mambaforge to miniforge

[fstagni]

https://conda-forge.org/news/2024/07/29/sunsetting-mambaforge/

[aldbr]

I've just realized that #7837 only targeted integration 😅

Btw, I am not entirely sure that this comment has been addressed: #7837 (comment)

[fstagni]

Well I did not change the Action like it was done in Chris' PR.

The documentation should be updated also, but TBH I am feeling lazy...

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/11658802099

Failed:

• integration
  cherry-pick bb24b5c into integration failed
  check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-bb24b5c9a-integration
  git cherry-pick -x -m 1 bb24b5c9a
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #7869 fix: from mambaforge to miniforge' --author='Federico Stagni <[email protected]>'
  git push -u origin cherry-pick-2-bb24b5c9a-integration
  
  # If you have the GitHub CLI installed the PR can be made with
  gh pr create \
       --label 'sweep:from rel-v8r0' \
       --base integration \
       --repo DIRACGrid/DIRAC \
       --title '[sweep:integration] fix: from mambaforge to miniforge' \
       --body 'Sweep #7869 `fix: from mambaforge to miniforge` to `integration`.
  
  Adding original author @fstagni as watcher.
  
  
  Closes #7870'