feat: add test for e501

[codomposer]

Summary

Add tests for the E501 maximum line length check in pycodestyle

Changes

• Add test_max_line_length_reports_e501_for_long_line to verify that a line longer than MAX_LINE_LENGTH correctly reports E501 line too long.
• Add test_max_line_length_ignores_long_shebang to verify that an overly long shebang on the first line is ignored, as intended by the maximum_line_length check.

Testing

• Ran pytest tests/test_api.py locally and confirmed all tests pass.

Contribution by Gittensor, learn more at https://gittensor.io/

[codomposer]

@asottile
can you please check this pr?

[sigmavirus24]

@codomposer people sleep and have jobs. There no need to mention then for a pr review