Fix flaky iness of opennav_docking test_docking_server test

[ewak]

Bug report

Required Info:

• Operating System:
  • Ubuntu 24.04
• Computer:
  • Intel x86_64
• ROS2 Version:
  • rolling
• Version or commit hash:
  • 13f728a
• DDS implementation:
  • rmw_cyclonedds_cpp

Steps to reproduce issue

sudo apt install python3-flaky
python3 -u -m pytest --min-passes 3 --max-runs 3 --force-flaky -s -v  ~/nav2_ws/src/navigation2/nav2_docking/opennav_docking/test/test_docking_server.py

Expected behavior

Tests pass

Actual behavior

Test is flaky and only sometimes passes.

Reproduction instructions

Additional information