resourceHealthChecks for APIs with no Group is generated incorrectly

[Gerald Nunn]

Describe the bug

Defining a health check with resourceHealthChecks for APIs like PersistentVolumeClaim just has a Kind and no group results in the following being generated in argocd-cm which does not work:

  resource.customizations.health._PersistentVolumeClaim: |

I think however this needs to be generated as follows without the underscore:

  resource.customizations.health.PersistentVolumeClaim: |

To Reproduce
Steps to reproduce the behavior:

1. In the Argo CD Spec define a resourceHealthCheck for an object with no group, for example:

  resourceHealthChecks:
    - kind: PersistentVolumeClaim
      check: |
        hs = {}
        if obj.status ~= nil then
          if obj.status.phase ~= nil then
            if obj.status.phase == "Pending" then
              hs.status = "Healthy"
              hs.message = obj.status.phase
              return hs
            end
            if obj.status.phase == "Bound" then
              hs.status = "Healthy"
              hs.message = obj.status.phase
              return hs
            end
          end
        end
        hs.status = "Progressing"
        hs.message = "Waiting for PVC"
        return hs

Expected behavior

The generated value in argocd-cm should not include the prefix underscore.