Jetpack QOL tweaks (#9563)

Content.Client/Movement/Systems/JetpackSystem.cs

@@ -56,6 +56,12 @@ public sealed class JetpackSystem : SharedJetpackSystem
 
     private void CreateParticles(EntityUid uid)
     {
+        // Don't show particles unless the user is moving.
+        if (Container.TryGetContainingContainer(uid, out var container) &&
+            TryComp<PhysicsComponent>(container.Owner, out var body) &&
+            body.LinearVelocity.LengthSquared < 1f)
+            return;
+
         var uidXform = Transform(uid);
         var coordinates = uidXform.Coordinates;
         var gridUid = coordinates.GetGridUid(EntityManager);