Fix for incorrect setting

Author: SilkeSchomann

.github/workflows/unit_tests.yml

@@ -21,7 +21,6 @@ jobs:
           miniforge-version: latest
           activate-environment: mslice-env
           environment-file: environment.yml
-          conda-remove-defaults = "true"
           auto-activate-base: false
 
       - name: Install Mantid