Print the color channel format (RGB) for datum stats command

[vinnamkim]

Summary

• Ticket no. 137105 and GH issue datum stats output format  #1367
• Print the color channel format as well (RGB)
• Change the statistic accumulation logic to use ImageColorChannel context

How to test

Revisit the unit test as well to cover this change

Checklist

• I have added unit tests to cover my changes.​
• I have added integration tests to cover my changes.​
• I have added the description of my changes into CHANGELOG.​
• I have updated the documentation accordingly

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below).

# Copyright (C) 2024 Intel Corporation
#
# SPDX-License-Identifier: MIT

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (releases/2.0.0@26f95ed). Click here to learn what that means.

Additional details and impacted files

@@                Coverage Diff                @@
##             releases/2.0.0    #1389   +/-   ##
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  Coverage                  ?   80.82%           
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  Files                     ?      270           
  Lines                     ?    30668           
  Branches                  ?     6198           
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  Hits                      ?    24788           
  Misses                    ?     4491           
  Partials                  ?     1389           

Flag	Coverage Δ
windows-2022_Python-3.10	80.82% <100.00%> (?)

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