operator: Replace dead documentation link (#23777)

Before this patch, the documentation link generated for the Operator
page resulted in a 404 Not Found on Github pages.

With this change, the documentation link points to the "Operator" anchor
in the Keycloak docs index. Note that the operator docs don't seem to be
versioned on the Keycloak website.

operator/src/main/java/org/keycloak/operator/controllers/KeycloakSharedCsvMetadata.java

@@ -41,7 +41,7 @@ import io.quarkiverse.operatorsdk.bundle.runtime.SharedCSVMetadata;
     },
     links = {
         @CSVMetadata.Link(
-            url = "https://www.keycloak.org/docs/latest/server_installation/index.html#_operator",
+            url = "https://www.keycloak.org/guides#operator",
             name = "Documentation"
         ),
         @CSVMetadata.Link(