chore(ci): split dotnet restore and test in CI

.gitea/workflows/deploy-socialize.yml

@@ -36,7 +36,9 @@ jobs:
              mkdir -p \"\$workdir\"
              tar -xzf - -C \"\$workdir\"
              cd \"\$workdir\"
-             dotnet test backend/Socialize.slnx"
+             find . -type d \( -name bin -o -name obj \) -prune -exec rm -rf {} +
+             dotnet restore backend/Socialize.slnx
+             dotnet test backend/Socialize.slnx --no-restore"
 
   image:
     needs: test