Fix volume fsType handling for CSI volumes

```improvement operator
An issue causing CSI PV to do not have set `spec.csi.fsType` is now fixed. The csi-provisioner is now started with `--default-fstype=ext4` which is the default fstype to be used when there is no fstype specified in the StorageClass.
```

Co-authored-by: vpnachev <vladimir.nachev@sap.com>
Signed-off-by: ialidzhikov <i.alidjikov@gmail.com>

charts/internal/seed-controlplane/charts/csi-driver-controller/templates/deployment-csi-driver-controller.yaml

@@ -85,6 +85,7 @@ spec:
         - --kubeconfig=/var/lib/csi-provisioner/kubeconfig
         - --feature-gates=Topology=true
         - --volume-name-prefix=pv-{{ .Release.Namespace }}
+        - --default-fstype=ext4
         - --leader-election
         - --leader-election-namespace=kube-system
         - --v=5