text: Title: Get rid of duplicate set of metrics for watch counts
  Body: Just noticed that we have redundant metrics for watch counts like:
  
  ```
  # HELP apiserver_longrunning_gauge [ALPHA] Gauge of all active long-running apiserver requests broken out by verb, group, version, resource, scope and component. Not all requests are tracked this way.
  # TYPE apiserver_longrunning_gauge gauge
  apiserver_longrunning_gauge{component="apiserver",group="",resource="configmaps",scope="cluster",subresource="",verb="WATCH",version="v1"}
   1
  apiserver_longrunning_gauge{component="apiserver",group="",resource="configmaps",scope="namespace",subresource="",verb="WATCH",version="v1"} 25
  ```
  ^ This was added in v1.9 as part of https://github.com/kubernetes/kubernetes/pull/52302
  
  ```
  # HELP apiserver_registered_watchers [ALPHA] Number of currently registered watchers for a given resources
  # TYPE apiserver_registered_watchers gauge
  apiserver_registered_watchers{group="",kind="ConfigMap",version="v1"} 26
  ```
  ^ This was added in v1.11 as part of https://github.com/kubernetes/kubernetes/pull/63779
  
  We probably should get rid of the latter since the former is more granular and also includes other long-running calls (like proxy). Both seem to be in alpha status FWIW.
  
  /cc @wojtek-t @smarterclayton (authors for those changes)
  /sig instrumentation
  /good-first-issue