Treat deprecations seriously - deprecation in websockets

[evnchn]

Motivation

https://websockets.readthedocs.io/en/stable/howto/upgrade.html, and we have 5 years to migrate.

The deadline is 2030 so we're 5 years early, but I guess that's better than being late (🤡).

Implementation

WebSocket protocol configuration:

• Sets the ws parameter to 'wsproto' when configuring the Uvicorn server in nicegui/ui_run.py
  • We can choose anything but auto (defaults to the websockets legacy) and websockets
  • Personally believe that by using wsproto, which is more low-level, we may have performance increase.
  • But we may use websockets-sansio as well.

Test configuration cleanup:

• Removes deprecated warning filters related to the websockets.legacy and uvicorn.protocols.websockets modules from the filterwarnings section in pyproject.toml, as these are no longer needed.

Progress

• I chose a meaningful title that completes the sentence: "If applied, this PR will..."
• The implementation is complete.
• Pytests have been added (or are not necessary).
• Documentation has been added (or is not necessary).