Enhance unit test coverage

[oruebel]

Motivation

Add unit tests to enhance overall test coverage for

• Added unit tests for missed logic in core.py, image.py, spec.py, icephys.py, epoch.py
• Fixed bug in IntracellularRecordingsTable, the IntracellularResponseTable was not being initialized correctly when empty category tables were provided
• Fixed shape check in SpikeEventSeries to handle the case where AbstractDataChunkIterator are used for timestamps/data

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running ruff check . && codespell from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.

Project coverage is 94.22%. Comparing base (bc12931) to head (a06e9d4).

Files with missing lines	Patch %	Lines
src/pynwb/ecephys.py	80.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #2031      +/-   ##
==========================================
+ Coverage   91.73%   94.22%   +2.48%     
==========================================
  Files          27       27              
  Lines        2722     2718       -4     
  Branches      710      708       -2     
==========================================
+ Hits         2497     2561      +64     
+ Misses        149       94      -55     
+ Partials       76       63      -13     

Flag	Coverage Δ
integration	73.14% <27.27%> (+0.18%)	⬆️
unit	84.76% <90.90%> (+2.47%)	⬆️

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[oruebel]

@stephprince should this PR target the dev or the release branch for the 3.0 release?

[stephprince]

@stephprince should this PR target the dev or the release branch for the 3.0 release?

Since you mentioned there are breaking changes, I think this should target the 3.0 release branch. But I can review and take a closer look.

[oruebel]

I think this should target the 3.0 release branch. But I can review and take a closer look.

Sounds good. Feel free to modify the PR as necessary.

If you prefer, it should be pretty straight forward to just move the breaking changes to a separate PR since its just removes a few functions that were no longer used anywhere.

[oruebel]

@stephprince @rly to simplify things I have moved all breaking changes to a new PR #2036. This PR is good to go from my end.