mixing up label and value pairs when observing data in Prometheus endpoint.

[janithcmw]

When observing the published data to the Prometheus server via the Prometheus extension of WSO2SI, the label and value pairs of the response from the Prometheus server are getting mixed up.

This can be reproduced by using the default Prometheus sample which is shipped with the WSO2SI. To reproduce it is required to publish an extra parameter(at least three parameters) to the Prometheus server by changing the stream definition.