refactor(opentelemetry-sdk-node): simplify calculation of traceExportersList

[cjihrig]

Which problem is this PR solving?

This simplifies a calculation by avoiding repeated work.

Fixes # N/A

Short description of the changes

filterBlanksAndNulls() calls map() on an array of strings, and trim()s each element. Then, filter()s out empty strings and the string 'null'. However, traceExportersList is computed using the result of getStringListFromEnv(), which also trims and filters out empty strings. So, the only work that needs to be added here, is the filtering of 'null'. This saves a map() loop and simplifies the filter() call.

This was the only call site of filterBlanksAndNulls(). If it's OK, I can remove that function as well (it seems OK, but is exported from utils.ts).

I also noticed something that might be a bug related to the validation of 'none', but it almost seems intentional. If traceExportersList[0] === 'none', then getSpanProcessorsFromEnv() returns []. However, there is separate validation logic for the case where 'none' is mixed with other exporters. As the code is currently written, that second piece of validation logic would not catch the case where 'none' is the first element in traceExportersList, but the list also contains other exporters. If this is a bug, I can fix it in a followup. If it's intentional, maybe a comment should be added.

Type of change

None of these. Performance refactor.

How Has This Been Tested?

• Test suite.

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.21%. Comparing base (9688512) to head (bbfaff7).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6132      +/-   ##
==========================================
- Coverage   95.21%   95.21%   -0.01%     
==========================================
  Files         316      316              
  Lines        9390     9389       -1     
  Branches     2168     2167       -1     
==========================================
- Hits         8941     8940       -1     
  Misses        449      449              

Files with missing lines	Coverage Δ
...ental/packages/opentelemetry-sdk-node/src/utils.ts	92.24% <100.00%> (-0.06%)	⬇️

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[maryliag]

Thank you for the changes, and you can remove the function completely, looking at the history, I can see it was created for this use case, and since is no longer needed, it's safe to remove it.

About your question regarding the none, you can ignore it, because I'm making changes to this package (and the config one) that will solve this problem.

[otelbot]

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