Update to Priority Status Display Logic for EVS Streaming Data Source

We heard the need to update the priority status display logic to ensure that the fields reflect real-time job upgrades.

We changed how priority status updates are reflected in the last_upgrade_status_code, last_upgrade_status and last_upgrade_status_response fields. These fields will now only display a priority status if there is an upgrade from dirty to CleanNext, Stat, udef8, or udef9. A change from CleanNext, Stat, udef8, or udef9 to dirty is considered a downgrade and will cause the field to display as null. Additionally, a status change from dirty to blocked is not considered an upgrade, so the field will be set to null in these cases. The same rules will also apply to last upgrade status response. Finally, a change from Dirty to CleanNext and then back to dirty will result in last upgrade status continuing to show CleanNext, as this was the last status when the job was upgraded.