CI: remove unneeded multipass for snap build

.github/workflows/CI.yml

@@ -53,12 +53,9 @@ jobs:
         
         # workaround for GithubActionsCI+snapcraft, see https://forum.snapcraft.io/t/permissions-problem-using-snapcraft-in-azure-pipelines/13258/14
         sudo chown root:root /
+
         snapcraft --version
         
-        # use multipass provider as lxd doesn't work for some reason
-        sudo snap install multipass
-        sudo snap set snapcraft provider=multipass
-        
     - name: Build
       run: |
         dotnet build --configuration Release