fix: set `automountServiceAccountToken` in `backup-restore.yaml` test pod

General MR

Summary

Tests in bibgang are failing for this package do to the velero service account no longer having automountServiceAccount token set to true by default. This MR sets automountServiceAccountToken to true for the velero-script-test pod which is provisioned as part of bbtests. The pod needs access to the kube api server in order to perform its test functions.

Relevant logs/screenshots

The connection to the server localhost:8080 was refused - did you specify the right host or port?

Link to error: https://repo1.dso.mil/big-bang/bigbang/-/jobs/29718421#L3675

Relates big-bang/bigbang#1881 (closed)