`collection='ga_gm_3'` in `bandindices.calculate_indices()` no longer needed

[GL-S]

I think the 'ga_gm_3' is no longer needed with the new geomedian, as now the band names are the same of the ARD ones. If you use geomedian to calculate the indices you would need to use 'ga_ls_3' anyway now.

dea-notebooks/Tools/dea_tools/bandindices.py

Line 399 in 2bd9be0

elif collection == "ga_gm_3":

[robbibt]

Yes, I think I agree, that was just a temporary stop gap and it would be simpler to remove it

[GL-S]

Happy to make a PR and some testing at the next innovation day!