refactor(otlp-exporter-base): simplify isExportHTTPErrorRetryable()

[cjihrig]

Which problem is this PR solving?

isExportHTTPErrorRetryable() currently creates a throwaway array (more garbage for the garbage collector) and iterates over it. The number of cases is very small, so this function can be simplified to a single if statement.

Fixes # N/A

Short description of the changes

This commit simplifies isExportHTTPErrorRetryable() to an if statement.

Type of change

None of these.

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 95.39%. Comparing base (6a64439) to head (ec76320).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6249   +/-   ##
=======================================
  Coverage   95.39%   95.39%           
=======================================
  Files         314      314           
  Lines        9513     9516    +3     
  Branches     2194     2198    +4     
=======================================
+ Hits         9075     9078    +3     
  Misses        438      438           

Files with missing lines	Coverage Δ
...ages/otlp-exporter-base/src/is-export-retryable.ts	100.00% <100.00%> (ø)

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[otelbot]

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