Failure to initialize cloudfoundry http client

[jsoriano]

Cloudfoundry input fails to initialize with the following error:

2021-10-05T21:16:41.114-0700    ERROR   [input.cloudfoundry-v1] compat/compat.go:122    Input 'cloudfoundry-v1' failed with: expected http transport on client

Issue is probably related to the changes in http clients in #25219, doppler consumer expects a transport that has probably a different type now, here:

beats/x-pack/libbeat/common/cloudfoundry/dopplerconsumer.go

Lines 41 to 44 in 23e4403

	transport, ok := client.Transport.(*http.Transport)
	if !ok {
	return nil, fmt.Errorf("expected http transport on client")
	}

Investigate how this could have been detected by tests.

For confirmed bugs, please report:

• Version: 7.14.0, 7.15.0, 7.15.1
• Steps to Reproduce: Use the cloudfoundry input with Filebeat 7.14.0.

cc @bvader

[elasticmachine]

Pinging @elastic/integrations (Team:Integrations)