Missing org.alluxio metrics if Alluxio cache is enabled for multiple catalogs

[jingyi-dd]

When enabling Alluxio cache for multiple catalogs, the JMX metrics under org.alluxio are tied to only one catalog. And it doesn't seem to be deterministic which catalog it's initialized with.

[raunaqmorarka]

I think this #24514 should resolve it

[jingyi-dd]

I think this #24514 should resolve it

Thank you for the quick fix!