Properly handle missile units shooting more missile units (#8359)

* Properly handle missile units shooting more missile units

* Remove `shooter`, just pass down the owner

core/src/mindustry/entities/bullet/BulletType.java

@@ -554,7 +554,7 @@ public class BulletType extends Content implements Cloneable{
 
     public void init(Bullet b){
 
-        if(killShooter && b.owner() instanceof Healthc h){
+        if(killShooter && b.owner() instanceof Healthc h && !h.dead()){
             h.kill();
         }
 
@@ -700,7 +700,6 @@ public class BulletType extends Content implements Cloneable{
         return create(owner, team, x, y, angle, -1, velocityScl, lifetimeScl, null);
     }
 
-
     public @Nullable Bullet create(Entityc owner, Team team, float x, float y, float angle, float velocityScl, float lifetimeScl, Mover mover){
         return create(owner, team, x, y, angle, -1, velocityScl, lifetimeScl, null, mover);
     }
@@ -732,24 +731,27 @@ public class BulletType extends Content implements Cloneable{
                 Unit spawned = spawnUnit.create(team);
                 spawned.set(x, y);
                 spawned.rotation = angle;
+
                 //immediately spawn at top speed, since it was launched
                 if(spawnUnit.missileAccelTime <= 0f){
                     spawned.vel.trns(angle, spawnUnit.speed);
                 }
+                
                 //assign unit owner
                 if(spawned.controller() instanceof MissileAI ai){
                     if(owner instanceof Unit unit){
                         ai.shooter = unit;
                     }
-
                     if(owner instanceof ControlBlock control){
                         ai.shooter = control.unit();
                     }
-
                 }
                 spawned.add();
             }
 
+            //Since bullet init is never called, handle killing shooter here
+            if(killShooter && owner instanceof Healthc h && !h.dead()) h.kill();
+
             //no bullet returned
             return null;
         }