refactor(sdk-logs): remove unnecessary closure in _maybeStartTimer()

[cjihrig]

Which problem is this PR solving?

_maybeStartTimer() creates an unnecessary closure in order to invoke flush() from a timer. This creates unnecessary overhead at runtime.

Fixes # N/A

Short description of the changes

This commit removes the unnecessary closure.

Type of change

Perf 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 95.48%. Comparing base (f15aa7e) to head (6870764).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6361   +/-   ##
=======================================
  Coverage   95.48%   95.48%           
=======================================
  Files         363      363           
  Lines       11564    11564           
  Branches     2669     2669           
=======================================
  Hits        11042    11042           
  Misses        522      522           

Files with missing lines	Coverage Δ
...sdk-logs/src/export/BatchLogRecordProcessorBase.ts	92.22% <100.00%> (ø)

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[cjihrig]

Oh, it looks like this won't be necessary with #6356. I'll close this.