PIP-274: Add metric prefix for `topic_load_times`

[Technoboy-]

Motivation

The metrics are all started with pulsar_, so that both users and operators can quickly find the metrics of the entire system through this prefix. However, due to some other reasons, it was found that topic_load_times was missing the prefix, so want to get it right.

Proposed changes

In master branch, change :

• topic_load_times: -> pulsar_topic_load_times

[michaeljmarshall]

I think this should be PIP 274. I created PIP 273 here #20453

[asafm]

Can you please close the issue and follow the new PR process. If you would follow, you wouldn't get the number wrong.
https://github.com/apache/pulsar/blob/master/pip/README.md

[Technoboy-]

I think this should be PIP 274. I created PIP 273 here #20453

Thanks

[Technoboy-]

Can you please close the issue and follow the new PR process. If you would follow, you wouldn't get the number wrong. https://github.com/apache/pulsar/blob/master/pip/README.md

Thanks