Refresh ProjectileSource for projectiles

Makes sure the value returned by Projectile#getShooter in
the API matches the owner UUID specified in the entity nbt.
Previously, after the entity reloaded, Projectile#getShooter
would return null, while the entity still had an owner.

Also fixes setting the shooter/owner to null actually
clearing the owner.

Co-authored-by: Warrior <50800980+Warriorrrr@users.noreply.github.com>

paper-server/src/main/java/org/bukkit/craftbukkit/entity/AbstractProjectile.java

@@ -60,6 +60,7 @@ public abstract class AbstractProjectile extends CraftEntity implements Projecti
 
     @Override
     public final org.bukkit.projectiles.ProjectileSource getShooter() {
+        this.getHandle().refreshProjectileSource(true); // Paper - Refresh ProjectileSource for projectiles
         return this.getHandle().projectileSource;
     }