ci: Don't depend on cached QNS results (mozilla#3123)

Author: larseggert

.github/actions/docker-build-qns/action.yml

@@ -64,10 +64,13 @@ runs:
       shell: bash
 
     - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
+      # FIXME: Turning caching on causes this error:
+      # `Failed to save: <h2>Our services aren't available right now</h2><p>We're working to restore all services as soon as possible. Please check back soon.</p>`
+      # Since this happens for *each* parallel QNS run, it's simply too noisy.
       with:
         python-version: 3.12
-        cache: 'pip'
-        cache-dependency-path: 'quic-interop-runner/requirements.txt'
+        # cache: 'pip'
+        # cache-dependency-path: 'quic-interop-runner/requirements.txt'
 
     - name: Install Python packages
       run: |