Error message for FS not mounted on GUI node is misleading in case of CNSA

[smitaraut]

Describe the bug
On a CNSA setup, when the primary filesystem is unmounted, volume provisioning results in below error-

12 10:24:16.337498    1 connection.go:186] GRPC error: rpc error: code = Internal desc = primary filesystem isf-scale is not mounted on GUI node of Primary cluster
I0812 10:24:16.337525    1 controller.go:753] CreateVolume failed, supports topology = false, node selected false => may reschedule = false => state = Finished: rpc error: code = Internal desc = primary filesystem isf-scale is not mounted on GUI node of Primary cluster
I0812 10:24:16.337568    1 controller.go:1099] Final error received, removing PVC dd49a8b0-fc32-41ed-a758-6383b8e532c7 from claims in progress
W0812 10:24:16.337583    1 controller.go:958] Retrying syncing claim “dd49a8b0-fc32-41ed-a758-6383b8e532c7”, failure 62
E0812 10:24:16.337603    1 controller.go:981] error syncing claim “dd49a8b0-fc32-41ed-a758-6383b8e532c7": failed to provision volume with StorageClass “ibm-spectrum-fusion-mgmt-sc”: rpc error: code = Internal desc = primary filesystem isf-scale is not mounted on GUI node of Primary cluster
I0812 10:24:16.337647    1 event.go:282] Event(v1.ObjectReference{Kind:“PersistentVolumeClaim”, Namespace:“ibm-spectrum-fusion-ns”, Name:“icspv-pdqrelscgf”, UID:“dd49a8b0-fc32-41ed-a758-6383b8e532c7”, APIVersion:“v1", ResourceVersion:“42119005”, FieldPath:“”}): type: ‘Warning’ reason: ‘ProvisioningFailed’ failed to provision volume with StorageClass “ibm-spectrum-fusion-mgmt-sc”: rpc error: code = Internal desc = primary filesystem isf-scale is not mounted on GUI node of Primary cluster
I0812 10:24:42.395892    1 reflector.go:530] sigs.k8s.io/sig-storage-lib-external-provisioner/v6/controller/controller.go:869: Watch close - *v1.PersistentVolume total 0 items received
I0812 10:25:21.262073    1 reflector.go:530] k8s.io/client-go/informers/factory.go:134: Watch close - *v1.StorageClass total 0 items received
I0812 10:26:34.167610    1 reflector.go:530] sigs.k8s.io/sig-storage-lib-external-provisioner/v6/controller/controller.go:872: Watch close - *v1.StorageClass total 0 items received

Here the message "primary filesystem isf-scale is not mounted on GUI node of Primary cluster" is misleading because there is no GUI node in CNSA.

To Reproduce
Steps to reproduce the behavior:

1. Deploy CNSA with CSI driver
2. Unmount the filesystem from the pod running on provisioner node
3. Create fileset PVC using dynamic provisioning

Expected behavior
Error message to be improved so something like "primary filesystem isf-scale is not mounted on required node of Primary cluster"