Condition for closing critical security tracking issues
Critical security tracking issues are opened as-needed, and are often opened in addition to a normal security tracking issue.
When we finish a critical security release, previously we had a step to close existing tracking issues and open a new one. This had the effect of closing the existing, incomplete normal security tracking issue, which was undesired.
This updates the template to manually close the critical issue, since we don't need to immediately create a new one.