Fix e2e CI: Pass empty restic retain policy for restore

[shubham-pampattiwar]

/cherry-pick-oadp-1.2

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kaovilai, shubham-pampattiwar, sseago

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/migtools/volume-snapshot-mover/blob/master/OWNERS)~~ [kaovilai,shubham-pampattiwar,sseago] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[shubham-pampattiwar]

/cherry-pick oadp-1.2

[openshift-cherrypick-robot]

@shubham-pampattiwar: #249 failed to apply on top of branch "oadp-1.2":

Applying: fix e2e CI
Using index info to reconstruct a base tree...
M   controllers/restic.go
Falling back to patching base and 3-way merge...
Auto-merging controllers/restic.go
CONFLICT (content): Merge conflict in controllers/restic.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 fix e2e CI
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

In response to [this](https://github.com/migtools/volume-snapshot-mover/pull/249#issuecomment-1623802909): >/cherry-pick oadp-1.2 Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[kaovilai]

250 cp this one