NIFI-16156: Add connector-scoped Controller Service GET so View Canva…

[mcgilman]

…s Go To Service works without Troubleshooting.

• Adding response merging for the Controller Service endpoints.

NIFI-16156: Add connector-scoped Controller Service GET so View Canvas Go To Service works without Troubleshooting

Problem

The "Go To Service" affordance on the property table needs to resolve a Controller Service by ID before it can navigate to it. For services managed by a Connector, the only existing lookup was GET /controller-services/{id}, which is gated so that it only succeeds while the Connector is in Troubleshooting mode. As a result, "Go To Service" was non-functional for Connector-managed services when viewing the canvas normally (outside Troubleshooting).

Changes

Backend (nifi-web-api)

• Added GET /connectors/{id}/controller-services/{controllerServiceId} to ConnectorResource, authorized via READ on the Connector resource (not the underlying service), and resolved through locateConnectorControllerService so it bypasses the Troubleshooting gate — mirroring the pattern already established for connector-scoped Controller Service state (NIFI-15549).
• Supports the standard uiOnly=true query param, stripping non-UI-relevant fields the same way ControllerServiceResource.getControllerService does.
• Added NiFiServiceFacade.getConnectorControllerService / StandardNiFiServiceFacade implementation.

Cluster response merging (nifi-framework-cluster)

• Registered the new endpoint's URI pattern with the existing ControllerServiceEndpointMerger, so GET responses across cluster nodes are properly merged (validation status/errors, bulletins, referencing-component permissions) instead of an arbitrary node's response being returned unmerged.
• Also closed a related pre-existing gap: the connector-scoped Controller Services list endpoint (GET /connectors/{id}/flow/process-groups/{processGroupId}/controller-services) had no merger registered either; added its pattern to the existing ControllerServicesEndpointMerger.

Toolkit client

• Added ConnectorClient.getControllerService / JerseyConnectorClient implementation for the new endpoint.

Frontend (nifi-frontend, upstream only)

• connector.service.ts: added getControllerService(connectorId, controllerServiceId).
• connector-canvas.effects.ts and connector-controller-services.effects.ts: wired goToService to call the new connector-scoped endpoint, then dispatch navigateToControllerService and close the dialog.
  • The fetch subscription tears down via takeUntil(dialogRef.afterClosed()) rather than the service's lifetime, so it doesn't outlive the dialog.
  • Navigation is dispatched before the dialog closes, avoiding a race between the two.
  • If the Connector id can't be resolved from the route, a banner error is dispatched instead of silently doing nothing.

Testing

• TestConnectorResource: new endpoint success, uiOnly=true, and not-authorized cases.
• StandardNiFiServiceFacadeTest: not-found case for the new facade method.
• New ControllerServiceEndpointMergerTest / ControllerServicesEndpointMergerTest: canHandle coverage for the connector-scoped patterns (including negative cases for malformed UUIDs, wrong HTTP method, and non-matching sub-paths).
• connector-canvas.effects.spec.ts / connector-controller-services.effects.spec.ts: success (fetch → navigate → close), HTTP error (banner error), and missing-connector-id (banner error, no HTTP call) cases for goToService in both dialogs.