In bm runner in run-workload function.

Flows that allow for --existing-resource-policy=update  are set via an options section in the yaml that can be dynamically allowed per case.

Meaning by default restore actions will remove source namespace before restore atte
mpts in all cases,
    except if dataset yaml contains existingResourcePolicy key in args set to 'U
pdate', then source namespace will NOT be removed.
    example snippet from dataset yaml of a restore:
    args:
        plugin: csi
        use_cli: true
        existingResourcePolicy: Update

    The above will result in source dataset not being removed.
    However if existingResourcePolicy is not defined or isnt set to 'Update'
    then source namespace will be removed before restore is attempted.

Please have a look at the code and scope out a solution that will allow for restore based on current code.  Additionally if we need to handle dataset specific changes to enable this test case then lets discuss it on this ticket.