[chore][exporter/azuremonitor] Force the telemetry to be sent to azuremonitor

[whitneygriffith]

Description

1. Resolved an issue where traces weren't being sent to App Insights due to not flushing the Telemetry Channel. Added the necessary flush operation to ensure all traces, metrics and logs are properly sent to the queue, leveraging App Insights' batch handling for more efficient processing.

Link to tracking issue

Resolves #35037

[andrzej-stencel]

Sounds like this is a bug fix. Can you add a changelog entry? https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#adding-a-changelog-entry

[whitneygriffith]

Sounds like this is a bug fix. Can you add a changelog entry? https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#adding-a-changelog-entry

I have added the changelog entry.

[andrzej-stencel]

There are some errors here: https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/11700948723/job/32586089416?pr=36172

Error: ./factory_test.go:20:25: cannot use &mockTransportChannel{} (value of type *mockTransportChannel) as transportChannel value in struct literal: *mockTransportChannel does not implement transportChannel (missing method Flush)

[fatsheep9146]

There are still some unresolved failed tests https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/11711127058/job/32641600088?pr=36172

=== FAIL: . TestExporterLogDataCallback (0.00s)
panic: 
	assert: mock: I don't know what to return because the method call was unexpected.
		Either do Mock.On("Flush").Return(...) first, or remove the Flush() call.
		This method was unexpected:
			Flush()
			
		at: [/home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/exporter/azuremonitorexporter/mock_transportChannel.go:24 /home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/exporter/azuremonitorexporter/logexporter.go:39 /home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/exporter/azuremonitorexporter/logexporter_test.go:118] [recovered]
	panic: 
	assert: mock: I don't know what to return because the method call was unexpected.
		Either do Mock.On("Flush").Return(...) first, or remove the Flush() call.
		This method was unexpected:
			Flush()
			
		at: [/home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/exporter/azuremonitorexporter/mock_transportChannel.go:24 /home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/exporter/azuremonitorexporter/logexporter.go:39 /home/runner/work/opentelemetry-collector-contrib/opentelemetry-collector-contrib/exporter/azuremonitorexporter/logexporter_test.go:118]

[fatsheep9146]

I think you should do as this lint said, could you please fix this? https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/11904647742/job/33173837807?pr=36172

Generated code is out of date, please run "make generate" and commit the changes in this PR.

[codeboten]

Closing and re-opening as it looks like the CI checks are stuck.

[codeboten]

Apparently I cannot reopen it :(

[fatsheep9146]

@whitneygriffith How about you create a same pr again? It seems that this pr is not able to be merged due to the stuck CI.

[whitneygriffith]

Created #36520