Use static dispatch in SimpleLogProcessor

[cijothomas]

Part of #1942
Given this is a breaking change, we should not merge until 0.27.1 is out.

Thanks @lalitb for helping with this. I will see if I can continue this to achieve the rest of ideas mentioned in 1942 and avoid dyn dispatch completely in Log hot path (not for Batch scenario+any custom)

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.5%. Comparing base (a3c469b) to head (4c24d47).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/logs/log_processor.rs	83.3%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2338   +/-   ##
=====================================
  Coverage   79.5%   79.5%           
=====================================
  Files        123     123           
  Lines      21492   21492           
=====================================
  Hits       17096   17096           
  Misses      4396    4396           

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