Nav Double Namespace fix

[hilary-luo]

Description

Don't push namespace to nav, it is handled in the nav launch files and was being applied twice.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Launch the simulation including slam, nav and/or localization in the same launch command and include a namespace. Verified that SLAM, Nav and localization all worked, specifically publishing / subscribing to the correct topics (don't have namespace duplicated).

# Run this command
ros2 launch turtlebot4_ignition_bringup turtlebot4_ignition.launch.py nav2:=true slam:=true rviz:=true namespace:=robot1

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation