Ensure noise is injected when the simulation is paused and a single step is manually requested

PiperOrigin-RevId: 807688008
Change-Id: I8de9706c633565d6d6944b58d34de9da1037a837

Author: okmatija

simulate/main.cc

@@ -380,6 +380,9 @@ void PhysicsLoop(mj::Simulate& sim) {
             syncSim = d->time;
             sim.speed_changed = false;
 
+            // inject noise
+            sim.InjectNoise();
+
             // run single step, let next iteration deal with timing
             mj_step(m, d);
             const char* message = Diverged(m->opt.disableflags, d);