Add Python 3.14 Support

[lola831]

Description

This PR adds support for Python 3.14 in Scenic, including CI , tox, and dependency updates.

Dependency updates

• Switched Scenic to use pygame-ce for Python 3.10+.
• Kept pygame for Python versions below 3.10, since pygame-ce only supports Python 3.10+.
• This change helps with Python 3.14 support, since pygame-ce provides Python 3.14 support.
• Because Scenic and VerifAI depend on each other, both need the same conditional pygame --> pygame-ce change for Python 3.10+. (Related VerifAI PR: PR #61)
• Updated the CARLA Python version guard from <= 3.10 to <= 3.12.

CI Support:

• Added Python 3.14 to the GitHub Actions test matrix (run-tests.yml)
• Enabled allow-prereleases: true to test against prereleases

Tox support:

• Extended tox.ini to include Python 3.14 environments
• Worked around an issue where scenic[metadrive] was being installed even when python_version > 3.11 by listing metadrive-simulator directly with the correct version guard

Pre-commit updates:

• Updated black and isort to run under Python 3.14

Sphinx compatibility:

• Increased the upper bound for sphinx to <8 to allow versions compatible with Python 3.14
• Patched object_description in conf.py to accept **kwargs for compatibility with Sphinx ≥7.2 (which passes a _seen kwarg) while remaining backward-compatible with older versions

Documentation:

• Added a note in the simulator docs reminding users that not all simulators may support the same range of Python versions, users should verify support per simulator.

Issue Link

Checklist

• I have tested the changes locally via pytest and/or other means
• I have added or updated relevant documentation
• I have autoformatted the code with black and isort
• I have added test cases (if applicable)

Additional Notes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.74%. Comparing base (1798eaa) to head (2960769).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #371      +/-   ##
==========================================
+ Coverage   89.72%   89.74%   +0.01%     
==========================================
  Files          48       48              
  Lines       13190    13190              
==========================================
+ Hits        11835    11837       +2     
+ Misses       1355     1353       -2     

see 3 files with indirect coverage changes

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