update Interoperator metrics doc

[cr7258]

The Interoperator metrics doc is outdated. Update the doc to match the correct label names:

• interoperator_service_instances_metrics_state
• interoperator_service_bindings_metrics_state

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: cr7258 / name: Se7en (2cd8141)

[codecov]

Codecov Report

Merging #1981 (2cd8141) into master (dd661d1) will decrease coverage by 0.39%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1981      +/-   ##
==========================================
- Coverage   72.89%   72.50%   -0.39%     
==========================================
  Files          48       48              
  Lines        4633     4633              
==========================================
- Hits         3377     3359      -18     
- Misses        907      921      +14     
- Partials      349      353       +4     

[agabrys]

Just in case - list of labels:

https://github.com/cloudfoundry/service-fabrik-broker/blob/v0.26.0/interoperator/controllers/multiclusterdeploy/sfserviceinstancemetrics/sfserviceinstancemetrics_controller.go#L46-L55