rqt-jtc: Add launch test

[christophfroehlich]

Description

Similar to the test added with ros-controls/ros2_control#3367

Is this user-facing behavior change?

no

Did you use Generative AI?

GPT Codex 5.3

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.51%. Comparing base (9f162e1) to head (69c8aff).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2405      +/-   ##
==========================================
+ Coverage   85.60%   86.51%   +0.90%     
==========================================
  Files         148      149       +1     
  Lines       15827    15851      +24     
  Branches     1339     1339              
==========================================
+ Hits        13549    13713     +164     
+ Misses       1792     1651     -141     
- Partials      486      487       +1     

Flag	Coverage Δ
unittests	86.51% <100.00%> (+0.90%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...oint_trajectory_controller/test/test_run_launch.py	100.00% <100.00%> (ø)

... and 5 files with indirect coverage changes

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[christophfroehlich]

@christianrauch do you also use rqt_joint_trajectory_controller? Is there anything we have to fix for Qt6?

[christianrauch]

I don't use the rqt_joint_trajectory_controller, and it will take a while until I can test it with lyrical.