keycloak-user-mgmt unwanted drift correction

see this error in https://gitlab.com/sylva-projects/sylva-core/-/jobs/12963931796:

   🔹 keycloak-user-management
      🔄 [2026-02-03T06:31:59.603Z] Memberships/keycloak/infra-admins changed (1 additions, 0 changes, 0 removals)","type":"Warning","object":{"kind":"HelmRelease","namespace":"sylva-system","name":"keycloak-user-management","uid":"6631ce45-dab7-4f5d-ad7e-9aca07e6c992","apiVersion":"helm.toolkit.fluxcd.io/v2","resourceVersion":"56371"},"reason":"DriftDetected}
      🔧 Patches applied:
        - [2026-02-03T06:31:59.603Z] Memberships/keycloak/infra-admins ->
          [
            {
              "value": "2026-02-03T06:31:59Z",
              "op": "add",
              "path": "/metadata/annotations/crossplane.io~1external-create-succeeded"
            }
          ]

We need to add /metadata/annotations/crossplane.io~1external-create-succeeded to the drift correction ignore list of the keycloak-user-management HelmRelease.