feat(instrumentation-grpc): monitor error events with events.errorMonitor

[cjihrig]

Which problem is this PR solving?

errorMonitor should be preferred over 'error' event handlers for instrumentation, as the latter alters the behavior of the server if the user has not added their own error handler.

Related to: #225. I'm not sure we want to close the issue based on this fix.

Short description of the changes

This commit updates instrumentation-grpc to utilize errorMonitor instead of 'error' event handlers. This makes the instrumented server behave more like it would without instrumentation.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Ran the test suite.
• Added an additional assertion for the 'error' handler count of the server.

Checklist:

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.54%. Comparing base (f927e82) to head (ab7dd28).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5369   +/-   ##
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  Coverage   94.54%   94.54%           
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  Files         318      318           
  Lines        8052     8053    +1     
  Branches     1694     1694           
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+ Hits         7613     7614    +1     
  Misses        439      439           

Files with missing lines	Coverage Δ
...ntelemetry-instrumentation-grpc/src/serverUtils.ts	90.66% <100.00%> (+0.12%)	⬆️