[CI] `test_set_pause_and_step_simulation` is flaky

[christophfroehlich]

Describe the bug

2026-04-19T04:38:01.3483252Z     -- run_test.py: verify result file '/home/runner/work/ros2_control_ci/ros2_control_ci/.work/target_ws/build/mujoco_ros2_control_tests/test_results/mujoco_ros2_control_tests/test_robot_launch_mjcf_generation_from_robot_description_test.py.xunit.xml'
2026-04-19T04:38:01.3484428Z   >>>
2026-04-19T04:38:01.3485456Z build/mujoco_ros2_control_tests/test_results/mujoco_ros2_control_tests/test_robot_launch_mjcf_generation_from_robot_description_test.py.xunit.xml: 13 tests, 0 errors, 1 failure, 1 skipped
2026-04-19T04:38:01.3486375Z - robot_launch_test.TestFixture test_set_pause_and_step_simulation
2026-04-19T04:38:01.3486688Z   <<< failure message
2026-04-19T04:38:01.3486889Z     Traceback (most recent call last):
2026-04-19T04:38:01.3494581Z       File "/home/runner/work/ros2_control_ci/ros2_control_ci/.work/target_ws/src/ros-controls/mujoco_ros2_control/mujoco_ros2_control_tests/test/robot_launch_test.py", line 539, in test_set_pause_and_step_simulation
2026-04-19T04:38:01.3495704Z         self.assertAlmostEqual(paused_clock_time, clock_time, delta=MUJOCO_TIMESTEP + 1e-7)
2026-04-19T04:38:01.3496330Z     AssertionError: 11.876 != 11.88 within 0.0020001 delta (0.004000000000001336 difference)
2026-04-19T04:38:01.3496759Z   >>>

To Reproduce
ros-controls/ros2_control_ci#746