[Ingest Manager] Enforce license level for custom registry URL (#79204)

* Enforce enterprise license for custom registry URL

* Add comments

x-pack/plugins/ingest_manager/README.md

@@ -8,7 +8,8 @@
   - [code for adding the routes](https://github.com/elastic/kibana/blob/1f27d349533b1c2865c10c45b2cf705d7416fb36/x-pack/plugins/ingest_manager/server/plugin.ts#L115-L133)
   - [Integration tests](server/integration_tests/router.test.ts)
 - Both EPM and Fleet require `ingestManager` be enabled. They are not standalone features.
-- For Gold+ license, a custom package registry URL can be used by setting `xpack.ingestManager.registryUrl=http://localhost:8080`
+- For Enterprise license, a custom package registry URL can be used by setting `xpack.ingestManager.registryUrl=http://localhost:8080`
+  - This property is currently only for internal Elastic development and is unsupported
 
 ## Fleet Requirements
 

x-pack/plugins/ingest_manager/common/services/license.ts

@@ -43,4 +43,11 @@ export class LicenseService {
       this.licenseInformation?.hasAtLeast('gold')
     );
   }
+  public isEnterprise() {
+    return (
+      this.licenseInformation?.isAvailable &&
+      this.licenseInformation?.isActive &&
+      this.licenseInformation?.hasAtLeast('enterprise')
+    );
+  }
 }

x-pack/plugins/ingest_manager/server/services/epm/registry/registry_url.ts

@@ -28,16 +28,19 @@ const getDefaultRegistryUrl = (): string => {
   }
 };
 
+// Custom registry URL is currently only for internal Elastic development and is unsupported
 export const getRegistryUrl = (): string => {
   const customUrl = appContextService.getConfig()?.registryUrl;
-  const isGoldPlus = licenseService.isGoldPlus();
+  const isEnterprise = licenseService.isEnterprise();
 
-  if (customUrl && isGoldPlus) {
+  if (customUrl && isEnterprise) {
     return customUrl;
   }
 
   if (customUrl) {
-    appContextService.getLogger().warn('Gold license is required to use a custom registry url.');
+    appContextService
+      .getLogger()
+      .warn('Enterprise license is required to use a custom registry url.');
   }
 
   return getDefaultRegistryUrl();