Description of problem:

**

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: |

Workaround
Previously `spec.resourceCustomizations` was still supported, so users could use that as a workaround, however with GitOps v1.10.0 we removed support for that method, so users have no workaround anymore 

Prerequisites (if any, like setup, operators/versions):

Steps to Reproduce

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

  Actual results:

cm entry is generated as
resource.customizations.health._PersistentVolumeClaim: |

Expected results:

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

Reproducibility (Always/Intermittent/Only Once):

Acceptance criteria: 

Definition of Done:

Build Details:

Additional info (Such as Logs, Screenshots, etc):

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