Rename `MicroManagerTiffImagingExtractor` channel to 'OpticalChannelDefault'

[weiglszonja]

Micro-Manager uses "Default" as channel name, it is better to rename it to 'OpticalChannelDefault' for clarity

[codecov[bot]]

Codecov Report

Merging #223 (475d6bc) into main (ae5f252) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #223   +/-   ##
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  Coverage   75.45%   75.46%           
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  Files          35       35           
  Lines        2514     2515    +1     
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+ Hits         1897     1898    +1     
  Misses        617      617           

Flag	Coverage Δ
unittests	75.46% <100.00%> (+<0.01%)	:arrow_up:

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Impacted Files	Coverage Δ
...gingextractors/micromanagertiffimagingextractor.py	99.15% <100.00%> (+<0.01%)	:arrow_up:

[CodyCBakerPhD]

I meant that you can modify it at the extractor level within the interface; the notion of the OpticChannel is NWB specific and the notion of the naming scheme is also NWB specific, so IDK that ROIExtractors would need to adopt it directly

[weiglszonja]

@CodyCBakerPhD I misunderstood it, let's do it that way.