Fix assignment with different chunks

[hombit]

Sorry for a lot of typing and ignore[] stuff — mypy got crazy on me.

Fix #294

[github-actions]

Before [728d785]	After [25b6dc6]	Ratio	Benchmark (Parameter)
39.1±0.2ms	40.0±0.4ms	1.02	benchmarks.ReassignHalfOfNestedSeries.time_run
27.1±0.4ms	27.3±0.5ms	1.01	benchmarks.AssignSingleDfToNestedSeries.time_run
134M	136M	1.01	benchmarks.CountNestedBy.peakmem_run
1.39±0ms	1.41±0.01ms	1.01	benchmarks.NestedFrameReduce.time_run
246M	246M	1	benchmarks.AssignSingleDfToNestedSeries.peakmem_run
65.8±0.3ms	65.5±1ms	1	benchmarks.CountNestedBy.time_run
101M	101M	1	benchmarks.NestedFrameAddNested.peakmem_run
10.6±0.06ms	10.6±0.06ms	1	benchmarks.NestedFrameAddNested.time_run
105M	104M	1	benchmarks.NestedFrameQuery.peakmem_run
10.5±0.02ms	10.5±0.04ms	1	benchmarks.NestedFrameQuery.time_run

Click here to view all benchmarks.

[codecov]

Codecov Report

❌ Patch coverage is 95.12195% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.63%. Comparing base (728d785) to head (6d0e997).
⚠️ Report is 108 commits behind head on main.

Files with missing lines	Patch %	Lines
src/nested_pandas/series/dtype.py	83.33%	1 Missing ⚠️
src/nested_pandas/series/utils.py	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #303      +/-   ##
==========================================
- Coverage   97.73%   97.63%   -0.10%     
==========================================
  Files          18       18              
  Lines        1631     1652      +21     
==========================================
+ Hits         1594     1613      +19     
- Misses         37       39       +2     

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[dougbrn]

Nice, looks good. Congrats on conquering mypy