Update logs gRPC exporter class name to singular OTLPLogExporter

[dyladan]

I did just notice that the name of this class has singular Log in its name, which is inconsistent with the existing gRPC exporter which has plural Logs. I think OTLPLogExporter (singular as here) is the right name - it's consistent with OTLPMetricExporter and OTLPTraceExporter, so I would leave it here as is, but we might want to go back and update the gRPC class name.

Originally posted by @martinkuba in #3764 (comment)

[fuaiyi]

I have submitted a PR to address this issue. #3819

[Vunovati]

Seems like this problem is still present: https://github.com/open-telemetry/opentelemetry-js/blame/main/experimental/packages/exporter-logs-otlp-proto/src/platform/node/OTLPLogsExporter.ts#L40

[pichlermarc]

Seems like this problem is still present: main/experimental/packages/exporter-logs-otlp-proto/src/platform/node/OTLPLogsExporter.ts#L40 (blame)

@Vunovati ah yes, that's a different exporter; please open a new issue so that we can track it separately.