Description of problem:

On the Grafana Dashboard `General / ACM - Clusters Overview`, the default label is cloud with value ALL.

But the BM cluster without lable cloud, so BM cluster is not list in this Dashboard by default. It would cause confuse sometimes for the user, and it's should display all clusters by default.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:

1. import one BM cluster into the Hub
2. Deploy MCOCR
3. Navigate to the Grafana Dashboard `General / ACM - Clusters Overview`
4. BM cluster is not list in this dashboard by default
   
5. 5. change label to vendor with value ALL, the BM cluster is list
   

Actual results:

Expected results:

Additional info: