Make Spent Casing Ejection Not Suck (#478)

# Description

Part of #467, #460, and #474

This is a small PR that corrects a math error in SharedGunSystem,
causing shell casings to be "Thrown" directly downwards instead of in an
actually cinematic and exciting arc. While I'm at it, I also corrected
the fixture of base shell casings to favor "Bounciness", and decreased
its mass to approximately 100 grams. Finally, I added a sound for when
casings bounce off of walls, which wasn't present before.


https://github.com/Simple-Station/Einstein-Engines/assets/16548818/56bb4ecc-d5eb-4b36-853b-42f05374150d

🆑
- fix: Spent bullet casings now fly away from a shooter in a cinematic
manner, rather than fall at their feet.

Co-authored-by: Danger Revolution! <[email protected]>

Content.Shared/Weapons/Ranged/Systems/SharedGunSystem.cs

@@ -443,7 +443,7 @@ protected void EjectCartridge(
         {
             Angle ejectAngle = angle.Value;
             ejectAngle += 3.7f; // 212 degrees; casings should eject slightly to the right and behind of a gun
-            ThrowingSystem.TryThrow(entity, ejectAngle.ToVec().Normalized() / 100, 5f);
+            ThrowingSystem.TryThrow(entity, ejectAngle.ToVec(), 625f);
         }
         if (playSound && TryComp<CartridgeAmmoComponent>(entity, out var cartridge))
         {

Resources/Prototypes/Entities/Objects/Weapons/Guns/Ammunition/Cartridges/base_cartridge.yml

@@ -11,10 +11,10 @@
         shape:
           !type:PhysShapeAabb
           bounds: "-0.10,-0.05,0.10,0.05"
-        density: 20
+        density: 0.5
         mask:
           - ItemMask
-        restitution: 0.3  # fite me
+        restitution: 0.7  # Small and bouncy
         friction: 0.2
   - type: Tag
     tags:
@@ -23,6 +23,11 @@
     size: Tiny
   - type: SpaceGarbage
   - type: EmitSoundOnLand
+    sound:
+      path: /Audio/Weapons/Guns/Casings/casing_fall_1.ogg
+      params:
+        volume: -1
+  - type: EmitSoundOnCollide
     sound:
       path: /Audio/Weapons/Guns/Casings/casing_fall_2.ogg
       params: