Color fixes for from_abgr_in and to_abgr_integer

[camkerr]

Fixes #2069

Summarize your change.

I renamed two Color functions to match the more common ABGR pattern:

• from_agbr_int > from_abgr_int
• to_agbr_integer > to_abgr_int

Not sure if this was a typo with the original implementation, or if this was intentional. Happy to discuss.

I also corrected the newly renamed from_abgr_int so that the order of the channels is correct. It was swapping the blue and green channels.

Reference associated tests.

I updated a few tests in test_color.py:

1. I added otio.core.Color.ORANGE to test_convert_to. Orange is the only colour in our predefined list where the red, green and blue channel values are unique, so good to have in there.
2. I updated test_from_abgr_int to use the "abgr" naming but also correctly convert 4281740498 to #d22c36ff.
3. I added test_to_abgr_int which was only tested previously using Black & White up in test_convert_to
4. I added test_abgr_round_trip which tests an int > hex > int round trip. Previously this would've failed due to the blue and green channel swapping.

LLM Use: Claude identified this problem. Code written by me.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.58%. Comparing base (fc5c58e) to head (aaf56aa).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2070      +/-   ##
==========================================
+ Coverage   83.56%   83.58%   +0.01%     
==========================================
  Files         182      182              
  Lines       13554    13570      +16     
  Branches     1260     1260              
==========================================
+ Hits        11326    11342      +16     
  Misses       2055     2055              
  Partials      173      173              

Flag	Coverage Δ
py-unittests	83.58% <100.00%> (+0.01%)	⬆️

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Files with missing lines	Coverage Δ
src/opentimelineio/color.cpp	96.73% <100.00%> (ø)
src/opentimelineio/color.h	66.66% <100.00%> (ø)
...entimelineio-bindings/otio_serializableObjects.cpp	84.46% <100.00%> (ø)
tests/test_color.py	94.73% <100.00%> (+1.40%)	⬆️

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[camkerr]

I also went ahead and renamed the to_abgr_integer to to_abgr_int.

If we're renaming functions, might as well tidy this up. Doesn't make sense to have one be "int" and the other "integer".