Non-problematic "Error unknown MAMBA_EXE" when installing DIRACOS2

In the DIRACOS2 installation there is an Error message displayed which is only printed in th logs:
`Error unknown MAMBA_EXE: "/diracos/conda.exe", filename must be mamba or micromamba`

I found it also in the CI test there: https://github.com/DIRACGrid/DIRACOS2/actions/runs/12237952625/job/34135481500#step:4:1440

This doesn't seem to affect anything but I just wanted to notice it.
