cleaning unnecessary files from repo root

[zzstoatzz]

removes:

• .ruff.toml was completely redundant bc the config was already in the pyproject.toml
• .codespellrc config into there as well and removes the extra file
• settings_schema.json (which has not changed in months) that lived at repo root since I assume its been superseded by schema/ (which has recently changed) but cc @desertaxle
• .gitattributes which was referring to src/prefect/_version which no longer exists with the new pyproject setup

[cicdw]

🧹

[codspeed-hq]

CodSpeed Performance Report

Merging #17235 will not alter performance

_{Comparing remove-rufftoml (fb92540) with main (29748d5)}

Summary

✅ 2 untouched benchmarks

[desertaxle]

Yup, this was definitely committed in error