Stand Your Ground law -- Prohibition -- Petition for writ of prohibition to prevent trial court from proceeding with Stand Your Ground immunity hearing based on claim that court will not apply statutory amendment which shifts burden of persuasion from defendant to state because court has found that amendment is an unconstitutional violation of separation of powers -- Because trial court has not heard or ruled on motion for Stand Your Ground immunity, but has only indicated that motion will be heard and that statutory amendment will not be applied, court has not acted in excess of its jurisdiction, and appellate court lacks jurisdiction to address petition for writ of prohibition before court hears defendant's motion and issues its ruling