Shotgun spread refactor (#27773)

* Moves spread data to new component

* Refactors shotgun spread code

* Makes shotgun cartridges and projectiles use new component

* Attempts to fix nullable build error

* Fixes hitscan weapons that I broke :(

* Saviour commit?

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Co-authored-by: EmoGarbage404 <retron404@gmail.com>

Content.Shared/Projectiles/ProjectileSpreadComponent.cs

@@ -0,0 +1,32 @@
+using Content.Shared.Weapons.Ranged.Systems;
+using Robust.Shared.GameStates;
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.Projectiles;
+
+/// <summary>
+/// Spawns a spread of the projectiles when fired
+/// </summary>
+[RegisterComponent, NetworkedComponent, Access(typeof(SharedGunSystem))]
+public sealed partial class ProjectileSpreadComponent : Component
+{
+    /// <summary>
+    /// The entity prototype that will be fired by the rest of the spread.
+    /// Will generally be the same entity prototype as the first projectile being fired.
+    /// Needed for ammo components that do not specify a fired prototype, unlike cartridges.
+    /// </summary>
+    [DataField(required: true)]
+    public EntProtoId Proto;
+
+    /// <summary>
+    /// How much the ammo spreads when shot, in degrees. Does nothing if count is 0.
+    /// </summary>
+    [DataField]
+    public Angle Spread = Angle.FromDegrees(5);
+
+    /// <summary>
+    /// How many prototypes are spawned when shot.
+    /// </summary>
+    [DataField]
+    public int Count = 1;
+}