Add str_length built-in check for PySpark backend

[marrov]

Adds a builtin-check for str_length for the pyspark.sql backend, solving these issues:

• 1311
• 1314

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 93.46%. Comparing base (812b2a8) to head (b002e70).
Report is 120 commits behind head on main.

Files	Patch %	Lines
pandera/backends/pyspark/builtin_checks.py	40.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1709      +/-   ##
==========================================
- Coverage   94.28%   93.46%   -0.82%     
==========================================
  Files          91      117      +26     
  Lines        7013     8856    +1843     
==========================================
+ Hits         6612     8277    +1665     
- Misses        401      579     +178     

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[cosmicBboy]

thanks @marrov ! please run pre-commit to fix linter errors: https://pandera.readthedocs.io/en/stable/CONTRIBUTING.html#set-up-pre-commit

[marrov]

thanks @marrov ! please run pre-commit to fix linter errors: https://pandera.readthedocs.io/en/stable/CONTRIBUTING.html#set-up-pre-commit

Yes, sorry for that I added it too hastily. Should be fixed now @cosmicBboy.

[cosmicBboy]

thanks @marrov ! sorry to extend this a little longer, but this check needs unit tests, which can live here: https://github.com/unionai-oss/pandera/blob/main/tests/pyspark/test_pyspark_check.py