Remove deprecated PF context measure from ContextMeasureSimple

[brandonhawi]

Summary

This PR removes the PF (Personal Fouls) context measure from the ContextMeasureSimple class as it has been deprecated by the NBA.com API.

Issue

Fixes #600

Details

The NBA.com API endpoint for shotchartdetail no longer returns data when using PF as a context measure. Other context measures such as FGA, FGM, PTS, EFG_PCT, and TS_PCT continue to function correctly.

This appears to be a backend change by the NBA, as Personal Fouls are not a relevant metric for filtering shot chart data (which focuses on shooting statistics).

Changes

• Removed pf = "PF" from the ContextMeasureSimple class in src/nba_api/stats/library/parameters.py

Testing

Users who were experiencing issues with the PF context measure returning no data should no longer be able to use this deprecated parameter, preventing confusion and API errors.

[swar]

Okay so things we will need to validate:

• Which endpoints are using ContextMeasure and confirm that PF is no longer supported in any of those endpoints.
• Once validated, we can be safe to remove. If it fails validation, we'll need to rethink the structure of this parameter since I am not a big fan of how I set all the parameter stuff up originally.

If you are able to confirm that, we can start moving! I can help out with confirmation if needed, just let me know.