Don't override col_cls in DynamicTable.add_column

[rly]

Motivation

Issue: If a user creates a schema that extends DynamicTableRegion or EnumData and tries to create a column with that subclass as the column class, the column is instead created with the base DynamicTableRegion or EnumData class.

For example, if a user creates a new type CustomDTR that extends the DynamicTableRegion type, and then they create a DynamicTable and calls add_column with the column class being set to the new type (col_cls=CustomDTR), then the new column for this table currently has type DynamicTableRegion.

    test_table.add_column(
            name='custom_dtr_column',
            description='this is a custom DynamicTableRegion column',
            col_cls=self.CustomDTR,
            table=True,
        )

See new test: test_add_custom_dtr_column

Another use case: if a user creates a new type CustomDTR that extends the DynamicTableRegion type, and they create a new type CustomTable that extends DynamicTable and contains a column with type CustomDTR, then the auto-generated column for this table currently has type DynamicTableRegion.

See test: test_custom_dtr_class

To make this work correctly in this PR, I updated add_column to use the passed col_cls instead of assuming table=True means col_cls=DynamicTableRegion. In order to do that, I also had to change the default value for col_cls away from VectorData. That default was set in more places than was needed anyway. I also had to move when the check that the passed col_cls equals the class included in a pre-defined column in __columns__ occurs, so that it is checked after col_cls is appropriately set, not before.

Checklist

• Did you update CHANGELOG.md with your changes?
• Does the PR clearly describe the problem and the solution?
• Have you reviewed our Contributing Guide?
• Does the PR use "Fix #XXX" notation to tell GitHub to close the relevant issue numbered XXX when the PR is merged?

[mavaylon1]

Will this be in by next milestone?

[VisLab]

Please let us know when it gets in. We are relying on it for implementation of ndx-hed.

[codecov]

Codecov Report

Attention: Patch coverage is 92.85714% with 1 line in your changes missing coverage. Please review.

Project coverage is 90.87%. Comparing base (775fa3b) to head (a5b6671).
Report is 1 commits behind head on dev.

Files with missing lines	Patch %	Lines
src/hdmf/common/table.py	92.30%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1091      +/-   ##
==========================================
- Coverage   90.88%   90.87%   -0.01%     
==========================================
  Files          42       42              
  Lines        9532     9537       +5     
  Branches     1922     1926       +4     
==========================================
+ Hits         8663     8667       +4     
  Misses        576      576              
- Partials      293      294       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.