fixed #1628: Fixed drill seargant completion reward drop bug

What has been done in this MR?

• Fixed timer of dropping reward if inventory is full during completion of drill sergeant random event. Original issue: #1628 (closed)

What should testers check?

• If inventory is full before entering event, complete event, and reward should drop on ground.
• Trigger event using command: ::revent -p player_name -e drill_demon

Additional note: This same code pulse edit is in other random events.

• I have tested these changes thoroughly.

• I used the relevant Thanos/Zaros tool for any JSON edits where possible, and have attached screenshots of any changes.