Fixed flood of errors on startup for mesh_filter

[JStech]

Description

The mesh filter was producing a flood of errors when it started, which stopped after a subscriber connected to its output. This prevents these errors, and instead produces a trickle of debug messages. I cleaned up a few little things, too, while I was at it.

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[codecov]

Codecov Report

Merging #2550 (1409ea6) into master (dd42164) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2550      +/-   ##
==========================================
+ Coverage   60.19%   60.21%   +0.02%     
==========================================
  Files         351      351              
  Lines       26492    26492              
==========================================
+ Hits        15945    15950       +5     
+ Misses      10547    10542       -5     

Impacted Files	Coverage Δ
...ma_kinematics_plugin/src/lma_kinematics_plugin.cpp	71.12% <0.00%> (-2.96%)	⬇️
...nning_scene_monitor/src/planning_scene_monitor.cpp	67.47% <0.00%> (-0.15%)	⬇️
...ipulation/pick_place/src/manipulation_pipeline.cpp	74.47% <0.00%> (+1.07%)	⬆️
...eit_ros/manipulation/pick_place/src/pick_place.cpp	92.23% <0.00%> (+3.34%)	⬆️
.../ompl_interface/src/detail/constrained_sampler.cpp	60.00% <0.00%> (+17.15%)	⬆️

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[simonschmeisser]

Would there also be a way for it to not complain at all when it has not yet received data (as opposed to incorrect data)? (haven't looked at the underlying code)

[JStech]

Would there also be a way for it to not complain at all when it has not yet received data (as opposed to incorrect data)? (haven't looked at the underlying code)

I think you're describing exactly what I'm fixing. When it has not yet received a depth map, the frame_id_ is the empty string.

[AndyZe]

Approved provided you make the small change in the while loop