Use Random port for listener in collector ext

[vasireddy99]

Use Random port for listener in collector ext in order to avoid error bind: address in use

[tylerbenson]

I don't fully understand how the sender knows which port to send data to, but this seems reasonable.

[serkan-ozal]

@vasireddy99 You also need to update receiver test too as it uses constant port: https://github.com/open-telemetry/opentelemetry-lambda/blob/main/collector/receiver/telemetryapireceiver/receiver_test.go#L119

[serkan-ozal]

I don't fully understand how the sender knows which port to send data to, but this seems reasonable.

@tylerbenson Its active port is registered here: https://github.com/open-telemetry/opentelemetry-lambda/blob/main/collector/internal/telemetryapi/client.go#L59

and it is called by here: https://github.com/open-telemetry/opentelemetry-lambda/blob/main/collector/internal/lifecycle/manager.go#L78

[vasireddy99]

@serkan-ozal good point, I looked into it initially since we are not testing httprequest but only the handler, and we are also using httptest it generates a valid http request irrespective of what we have provided, so probably be okay in my opinion.

[serkan-ozal]

Thanks for the fix @vasireddy99