Describe the bug (🐛 if you encounter this issue)

A backup target backed by a Samba server is not recognized. Due to the issue, the backups cannot be correctly listed.

To Reproduce

Steps to reproduce the behavior:

1. Create a LH cluster
2. Set up a Samba server and export a folder
3. Set up the backup target with CIFS mount point
4. The backup page cannot list backups correctly.

Expected behavior

A clear and concise description of what you expected to happen.

Log or Support bundle

If applicable, add the Longhorn managers' log or support bundle when the issue happens.
You can generate a Support Bundle using the link at the footer of the Longhorn UI.

Environment

• Longhorn version: 1.5.x and master
• Installation method (e.g. Rancher Catalog App/Helm/Kubectl):
• Kubernetes distro (e.g. RKE/K3s/EKS/OpenShift) and version:
  • Number of management node in the cluster:
  • Number of worker node in the cluster:
• Node config
  • OS type and version:
  • CPU per node:
  • Memory per node:
  • Disk type(e.g. SSD/NVMe):
  • Network bandwidth between the nodes:
• Underlying Infrastructure (e.g. on AWS/GCE, EKS/GKE, VMWare/KVM, Baremetal):
• Number of Longhorn volumes in the cluster:

Additional context

Add any other context about the problem here.