On target spells cast by non-actors should fire underwater

ProjectileManager::launchMagicBolt prevents ranged magic from working underwater. This appears to be correct when it comes to actors.

However, ranged spells cast by non-actors should result in a projectile being created. The created projectile should then explode straight away, potentially hitting nearby actors if it's an area of effect spell or if the actor happens to intersect the projectile. (Easily observed with kelp where it's possible to be inside the kelp when it casts the spell.)