Reduce code nesting. Runs ruff formatting.

[delucchi-cmu]

I was reading through method _validate_structs_from_schema, and thought it would be easier to follow the logic with conditionals treated more like guard clauses. This reduces the deepest indentation level in the method significantly.

Also ran ruff locally, and there were some unrelated changes.

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.23%. Comparing base (98071d5) to head (4c66c6e).

Files with missing lines	Patch %	Lines
src/nested_pandas/nestedframe/io.py	71.42%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #431      +/-   ##
==========================================
- Coverage   97.37%   97.23%   -0.14%     
==========================================
  Files          19       19              
  Lines        2132     2135       +3     
==========================================
  Hits         2076     2076              
- Misses         56       59       +3     

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[github-actions]

Before [98071d5]	After [13f8b43]	Ratio	Benchmark (Parameter)
failed	failed	n/a	benchmarks.ReadFewColumnsS3.peakmem_run
failed	failed	n/a	benchmarks.ReadFewColumnsS3.time_run
46.9±0.2ms	50.6±0.5ms	1.08	benchmarks.ReassignHalfOfNestedSeries.time_run
10.7±0.1ms	11.1±0.3ms	1.04	benchmarks.NestedFrameAddNested.time_run
178M	184M	1.03	benchmarks.ReadFewColumnsHTTPS.peakmem_run
263M	267M	1.02	benchmarks.ReassignHalfOfNestedSeries.peakmem_run
254M	256M	1.01	benchmarks.AssignSingleDfToNestedSeries.peakmem_run
66.4±0.3ms	67.1±0.4ms	1.01	benchmarks.CountNestedBy.time_run
139M	139M	1.00	benchmarks.CountNestedBy.peakmem_run
11.0±0.07ms	11.1±0.1ms	1.00	benchmarks.NestedFrameQuery.time_run

Click here to view all benchmarks.