Revert "feat: Add USE_GCLOUD_STORAGE_RSYNC=1 to Cloud Batch Jobs"

[hunsche]

Reverts google/clusterfuzz#5017

The original change aimed to migrate storage synchronization by enabling gcloud storage rsync. However, post-deployment monitoring revealed an issue: while gsutil rsync usage decreased as expected, there was no corresponding increase in gcloud storage rsync operations.

Following a "rollback first" policy to ensure system stability, this change reverts the feature enablement to allow for a more detailed investigation into the root cause of this discrepancy. The feature will be re-evaluated and potentially re-introduced after a thorough analysis