Make bullets inherit the velocity of the grid, not the gun or player (#27484)

Content.Server/Weapons/Ranged/Systems/GunSystem.cs

@@ -105,7 +105,7 @@ public sealed partial class GunSystem : SharedGunSystem
         // Update shot based on the recoil
         toMap = fromMap.Position + angle.ToVec() * mapDirection.Length();
         mapDirection = toMap - fromMap.Position;
-        var gunVelocity = Physics.GetMapLinearVelocity(gunUid);
+        var gunVelocity = Physics.GetMapLinearVelocity(fromEnt);
 
         // I must be high because this was getting tripped even when true.
         // DebugTools.Assert(direction != Vector2.Zero);