yarl.query_var not support prepare None

[IvanKirpichnikov]

Please confirm the following

• I agree to follow the aio-libs Code of Conduct

• I have checked the current issues for duplicates.

• I understand this is open source software provided for free and that I might not receive a timely response.
• I am positive I am NOT reporting a (potential) security
  vulnerability, to the best of my knowledge. (These must be shared by
  submitting this report form instead, if
  any hesitation exists.)

• I am willing to submit a pull request with reporoducers as xfailing test cases or even entire fix. (Assign this issue to me.)

Describe the bug

yarl does not support None processing in the query_var function

To Reproduce

import yarl

yarl._query.query_var(None)

Expected behavior

The function will return "null"

Logs/tracebacks

Traceback (most recent call last):
  File "<python-input-2>", line 1, in <module>
    yarl._query.query_var(None)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File "/home/ivank_kirpichnikov/Documents/projects/maxo/.venv/lib/python3.13/site-packages/yarl/_query.py", line 33, in query_var
    raise TypeError(
    ...<3 lines>...
    )
TypeError: Invalid variable type: value should be str, int or float, got None of type <class 'NoneType'>

Python Version

$ python --version
Python 3.13.3

multidict Version

$ python -m pip show multidict
Name: multidict
Version: 6.5.0
Location: /home/ivank_kirpichnikov/Documents/projects/maxo/.venv/lib/python3.13/site-packages
Requires:
Required-by: aiohttp, yarl

propcache Version

$ python -m pip show propcache
Name: propcache
Version: 0.3.2
Location: /home/ivank_kirpichnikov/Documents/projects/maxo/.venv/lib/python3.13/site-packages
Requires:
Required-by: aiohttp, yarl

yarl Version

$ python -m pip show yarl
Name: yarl
Version: 1.20.1
Location: /home/ivank_kirpichnikov/Documents/projects/maxo/.venv/lib/python3.13/site-packages
Requires: idna, multidict, propcache
Required-by: aiohttp

OS

Manjaro

Additional context

No response

[webknjaz]

Pretty sure it's not a bug. None has ambiguous semantics, just like any sentinels and booleans.