Remove the deprecated snapshot ID recording/retrieving method for pod volume backup

[Lyndon-Li]

In the current code (getVolumeBackupInfoForPod), we have two ways to retrieve the snapshot ID for a PVB, one is to get it from the PVB's status, the other is to get it from the pod's annotation. This means, there are two ways to saving the snapshot ID for a PVB, to the PVB's status or to the pod's annotation.

The latter way seems to be used by very old releases and we are not using it in the latest code.

Therefore, let's check and see if we can remove the latter way as it has been deprecated for a long time.

The deprecation message was added in v1.0.1 by PR #1577

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Closing the stale issue.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days. If a Velero team member has requested log or more information, please provide the output of the shared commands.

[Lyndon-Li]

Not stale

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days. If a Velero team member has requested log or more information, please provide the output of the shared commands.

[github-actions]

This issue was closed because it has been stalled for 14 days with no activity.