CSHARP-5783: Fix EG cleanup script (#1814)

Author: sanych-sun

evergreen/evergreen.yml

@@ -844,17 +844,11 @@ functions:
           fi
     - command: shell.exec
       params:
+        working_dir: mongo-csharp-driver
+        shell: "bash"
         script: |
           ${PREPARE_SHELL}
-          cd "$MONGO_ORCHESTRATION_HOME"
-          # source the mongo-orchestration virtualenv if it exists
-          if [ -f venv/bin/activate ]; then
-            . venv/bin/activate
-          elif [ -f venv/Scripts/activate ]; then
-            . venv/Scripts/activate
-          fi
-          mongo-orchestration stop
-          cd -
+          bash ${DRIVERS_TOOLS}/.evergreen/stop-orchestration.sh
           rm -rf $DRIVERS_TOOLS || true
     - command: subprocess.exec
       params: