allow dropna on nested columns as base columns

[dougbrn]

Change Description

Resolves #104

• My PR includes a link to the issue that I am addressing

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.76%. Comparing base (0bb042a) to head (de46a67).
Report is 52 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #105      +/-   ##
==========================================
- Coverage   98.77%   98.76%   -0.01%     
==========================================
  Files          15       15              
  Lines         895      894       -1     
==========================================
- Hits          884      883       -1     
  Misses         11       11              

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[github-actions]

Before [6152580]	After [ccbbf5b]	Ratio	Benchmark (Parameter)
31.5±2ms	32.8±4ms	1.04	benchmarks.AssignSingleDfToNestedSeries.time_run
259M	259M	1	benchmarks.AssignSingleDfToNestedSeries.peakmem_run
84M	84M	1	benchmarks.NestedFrameAddNested.peakmem_run
8.74±0.1ms	8.77±0.07ms	1	benchmarks.NestedFrameAddNested.time_run
88.2M	88.1M	1	benchmarks.NestedFrameQuery.peakmem_run
87.3M	87.2M	1	benchmarks.NestedFrameReduce.peakmem_run
6.27±0.09ms	6.21±0.08ms	0.99	benchmarks.NestedFrameQuery.time_run
278M	274M	0.99	benchmarks.ReassignHalfOfNestedSeries.peakmem_run
58.6±3ms	58.0±2ms	0.99	benchmarks.ReassignHalfOfNestedSeries.time_run
1.05±0ms	1.03±0ms	0.98	benchmarks.NestedFrameReduce.time_run

Click here to view all benchmarks.

[hombit]

Looks good!