Don't require ssl => true when using cloud_id

[jsvd]

If an output is configured with cloud_id only:

output {
  elasticsearch {
    cloud_id => '....'
    api_key => 'id:key' 
  }
}

we get an error:

[2022-01-19T10:36:54,206][ERROR][logstash.javapipeline    ][main] Pipeline error {:pipeline_id=>"main", :exception=>#<LogStash::ConfigurationError: Using api_key authentication requires SSL/TLS secured communication using the `ssl => true` option>, 

This is an unnecessary error since all of the Elastic cloud deployments must have TLS enabled, so TLS should be enabled automatically when cloud.id is set.