Describe the bug
Volume UI is displaying only the last backup

To Reproduce
Steps to reproduce the behavior:

1. Create a backup recurring job with retain >= 2, and a group
2. Associate this recurring job group to some volume
3. Wait for 2 or 3 backups be performed
4. See that volume UI displays only the last backup. Screenshots below.

Expected behavior
Volume UI displays 2 or more backups, within retain range.

Log

Environment:

• Longhorn version: 1.2.0
• Installation method (e.g. Rancher Catalog App/Helm/Kubectl): Rancher Catalog App
• Kubernetes distro (e.g. RKE/K3s/EKS/OpenShift) and version: RKE v1.20.9
  • Number of management node in the cluster: 3
  • Number of worker node in the cluster: 8
• Node config
  • OS type and version: Ubuntu 20.04.3 LTS kernel 5.4.0-84-generic
  • CPU per node: 4
  • Memory per node: 16 GB
  • Disk type(e.g. SSD/NVMe): SSD
  • Network bandwidth between the nodes:
• Underlying Infrastructure (e.g. on AWS/GCE, EKS/GKE, VMWare/KVM, Baremetal): VMWare
• Number of Longhorn volumes in the cluster: 23

Additional context
Wrong behaviour:

Wrong behaviour:

Right behaviour: