Some vehicle bugfixes (#11692)

Content.Shared/Movement/Systems/SharedMoverController.Relay.cs

@@ -13,6 +13,19 @@ public abstract partial class SharedMoverController
         SubscribeLocalEvent<RelayInputMoverComponent, ComponentShutdown>(OnRelayShutdown);
     }
 
+    /// <summary>
+    ///     Sets the relay entity and marks the component as dirty. This only exists because people have previously
+    ///     forgotten to Dirty(), so fuck you, you have to use this method now.
+    /// </summary>
+    public void SetRelay(EntityUid uid, EntityUid relayEntity, RelayInputMoverComponent? component = null)
+    {
+        if (!Resolve(uid, ref component))
+            return;
+
+        component.RelayEntity = relayEntity;
+        Dirty(component);
+    }
+
     private void OnRelayShutdown(EntityUid uid, RelayInputMoverComponent component, ComponentShutdown args)
     {
         // If relay is removed then cancel all inputs.