Make Python 3.14 experimental in the CI

```
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/urllib/request.py", line 1321, in do_open
    h.request(req.get_method(), req.selector, req.data, headers,
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              encode_chunked=req.has_header('Transfer-encoding'))
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/http/client.py", line 1358, in request
    self._send_request(method, url, body, headers, encode_chunked)
    ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/http/client.py", line 1404, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/http/client.py", line 1353, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/http/client.py", line 1113, in _send_output
    self.send(msg)
    ~~~~~~~~~^^^^^
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/http/client.py", line 1077, in send
    self.sock.sendall(data)
    ^^^^^^^^^^^^^^^^^
AttributeError: 'SSLContext' object has no attribute 'sendall'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.14.3/x64/lib/python3.14/site-packages/django/test/utils.py", line 461, in inner
    return func(*args, **kwargs)
  File "/home/runner/work/website/website/pmaweb/tests.py", line 173, in test_download
    self.cdn_tester(
    ~~~~~~~~~~~~~~~^
        Download,
```

Author: williamdes

.github/workflows/tests.yml

@@ -14,13 +14,18 @@ jobs:
   test-python:
     name: Test on Python ${{ matrix.python-version }} and ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ matrix.experimental }}
 
     strategy:
       fail-fast: false
       matrix:
         # Debian Trixie and Debian Forky (https://tracker.debian.org/pkg/python3)
-        python-version: ["3.13", "3.14"]
+        python-version: ["3.13"]
         os: [ubuntu-latest]
+        experimental: [false]
+        include:
+          # Debian Forky (https://tracker.debian.org/pkg/python3)
+          - { python-version: '3.14', experimental: true, os: ubuntu-latest }
 
     steps:
       - name: "Checkout code"