Fix throwing knockback when weightless (#2369)

* Fix throwing an item not moving the player when weightless

* Remove unnecessary code from ThrownItemComponent

* Fix velocity not stopping when hitting a wall after slipping when weightless

* Fix CanMove check being reversed

Content.Shared/Physics/ThrowKnockbackController.cs

@@ -0,0 +1,52 @@
+using Content.Shared.GameObjects.Components.Movement;
+using Content.Shared.GameObjects.EntitySystems;
+using Robust.Shared.Interfaces.Physics;
+using Robust.Shared.IoC;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics;
+
+namespace Content.Shared.Physics
+{
+    public class ThrowKnockbackController : VirtualController
+    {
+        [Dependency] private readonly IPhysicsManager _physicsManager = default!;
+
+        public ThrowKnockbackController()
+        {
+            IoCManager.InjectDependencies(this);
+        }
+
+        public void Push(Vector2 velocityDirection, float speed)
+        {
+            LinearVelocity = velocityDirection * speed;
+        }
+
+        private float Decay { get; set; } = 0.95f;
+
+        public override void UpdateAfterProcessing()
+        {
+            if (ControlledComponent == null)
+            {
+                return;
+            }
+
+            if (ControlledComponent.Owner.IsWeightless())
+            {
+                if (ActionBlockerSystem.CanMove(ControlledComponent.Owner)
+                    && ControlledComponent.IsColliding(Vector2.Zero, false))
+                {
+                    Stop();
+                }
+
+                return;
+            }
+
+            LinearVelocity *= Decay;
+
+            if (LinearVelocity.Length < 0.001)
+            {
+                Stop();
+            }
+        }
+    }
+}