fix(grpc): camelCase methods can be double patched

[markwolff]

Which problem is this PR solving?

• Fixes gRPC plugin issue | TypeError: Cannot read property 'replace' of undefined #1260

Short description of the changes

• RPC Methods defined with leading lowercase character, e.g. camelCaseMethod will be patched twice, leading to unexpected patching behavior.

[codecov]

Codecov Report

Merging #1289 into master will decrease coverage by 0.74%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1289      +/-   ##
==========================================
- Coverage   93.04%   92.29%   -0.75%     
==========================================
  Files         137      180      +43     
  Lines        3794     4490     +696     
  Branches      784      932     +148     
==========================================
+ Hits         3530     4144     +614     
- Misses        264      346      +82     

Impacted Files	Coverage Δ
packages/opentelemetry-api/src/api/global-utils.ts
...ges/opentelemetry-metrics/src/SumObserverMetric.ts
packages/opentelemetry-metrics/src/Metric.ts
...ckages/opentelemetry-exporter-zipkin/src/zipkin.ts
...pentelemetry-api/src/context/propagation/setter.ts
...ackages/opentelemetry-api/src/metrics/NoopMeter.ts
...telemetry-node/src/instrumentation/PluginLoader.ts
...elemetry-semantic-conventions/src/trace/general.ts
...rces/src/platform/node/detectors/AwsEc2Detector.ts
...s/opentelemetry-metrics/src/ValueObserverMetric.ts
... and 306 more

[dyladan]

LGTM when lint is fixed

[obecny]

lgtm

[mayurkale22]

lgtm

[dyladan]

@open-telemetry/javascript-maintainers all maintainers have approved this, I think we can merge it?