Prop 91: v6.7.0 Upgrade

This proposal aims to enable the definitive closure of all Leverage LP positions. Some positions (too small in size) were causing errors, preventing the closure of other positions at the same time. This patch fixes the issue and will permanently close all remaining Leverage LP positions. Reminder for those who have not yet done so: You now have three days (voting period) to close your positions manually before they are automatically closed during the next upgrade.