Fix the initial wrong periodicity reported by controller_manager

[saikishor]

This PR fixes the initial wrongly reported periodicity stats of the controller manager. This is happening as the initial iteration period is not properly scaled for this. This PR tends to fix this exact issue + also adds a wait for the node to wait for the proper clock to exist before continuing.

This should also fix the issue reported by @tonynajjar here: #1871 (comment)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.39%. Comparing base (fbfc01d) to head (3e3094f).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2018      +/-   ##
==========================================
+ Coverage   89.37%   89.39%   +0.02%     
==========================================
  Files         132      132              
  Lines       14649    14651       +2     
  Branches     1261     1261              
==========================================
+ Hits        13092    13097       +5     
+ Misses       1091     1088       -3     
  Partials      466      466              

Flag	Coverage Δ
unittests	89.39% <100.00%> (+0.02%)	⬆️

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

Files with missing lines	Coverage Δ
controller_manager/src/ros2_control_node.cpp	63.15% <100.00%> (+1.33%)	⬆️

... and 4 files with indirect coverage changes

[Rayman]

This issue is not yet fixed for me.

ros2 launch ros2_control_demo_example_1 rrbot.launch.py
ros2 topic echo /diagnostics

  message: 'Controller Manager has bad periodicity : 781.960720 Hz. Expected consistent 10 Hz'

I'm using the following version, which should include this fix

apt show ros-jazzy-controller-manager
Package: ros-jazzy-controller-manager
Version: 4.25.0-1noble.20250202.024429

[christophfroehlich]

can you try #2046 if it solves your issue?