Offline backup fails with `error pruning repository` error

Creating an offline backup with the OADP utility fails with the error message error pruning repository.

Symptoms

In the CPD-CLI*.log file, you see error messages like in the following example:

time=<timestamp> level=info msg=velero ns: oadp-operator
time=<timestamp> level=error msg=Backup "xxxxxx" does not exist.
time="<timestamp>" level=error msg=cpd-cli error="RunPluginCommand:Execution error: exit status 1" event=Exc

In the Velero log, you see an error message like in the following example:

time="<timestamp>" level=warning msg="error pruning repository" error="error running command=restic prune

In the velero-xxxx-xxxxx/velero-xxxx-xxxxx.yaml from the OADP must-gather tool, you see an OOMKilled error like in the following example:

- containerID: cri-o://b36031fce37cdd42dc0bf7b4c96997b33d2745c6f754e7c1419632229bf57e54
    image: registry.redhat.io/oadp/oadp-velero-rhel8@sha256:2c1c645410a77569705e5521f8abb652b2b46bcb6ee06b9650bde78fcf3e3061
    imageID: registry.redhat.io/oadp/oadp-velero-rhel8@sha256:2c1c645410a77569705e5521f8abb652b2b46bcb6ee06b9650bde78fcf3e3061
    lastState:
      terminated:
        containerID: cri-o://3bf3b24d6b6375a6526866fbf8e452bf457f8aa010c729ce1f0ad18059a5dffe
        exitCode: 137
        finishedAt: "2023-10-02T15:48:16Z"
        reason: OOMKilled
        startedAt: "<timestamp>"
    name: velero

Causes

An OOMKilled error occurred in the Velero pod.

Diagnosing the problem

Collect log information with the oadp gather info command.

Resolving the problem

In the DataProtectionApplication (DPA), increase the Velero memory limit.

Edit the DPA:
```
oc edit dpa -n ${OADP_OPERATOR_PROJECT}
```
Update the memory limit in the following places:
- spec.configuration.velero.podConfig.resourceAllocations.limits.memory
- spec.configuration.nodeAgent.podConfig.resourceAllocations.limits.memory

For example:

spec:
  configuration:
    velero:
      customPlugins:
      - image: ${CPDBR_VELERO_PLUGIN_IMAGE_LOCATION}
        name: cpdbr-velero-plugin
      defaultPlugins:
      - aws
      - openshift
      - csi
      podConfig:
        resourceAllocations:
          limits:
            cpu: "${VELERO_POD_CPU_LIMIT}"
            memory: 4Gi
          requests:
            cpu: 500m
            memory: 256Mi
      resourceTimeout: 60m
    nodeAgent:
      enable: true
      uploaderType: restic
      timeout: 72h
      podConfig:
        resourceAllocations:
          limits:
            cpu: "${NODE_AGENT_POD_CPU_LIMIT}"
            memory: 32Gi
          requests:
            cpu: 500m
            memory: 256Mi
        tolerations:
        - key: icp4data
          operator: Exists
          effect: NoSchedule