Fix std::placeholders namespace conflict

[henningkayser]

Fixes build error in #673

[codecov]

Codecov Report

Merging #713 (9214de8) into main (68553ff) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #713      +/-   ##
==========================================
+ Coverage   54.19%   54.19%   +0.01%     
==========================================
  Files         192      192              
  Lines       20186    20187       +1     
==========================================
+ Hits        10938    10939       +1     
  Misses       9248     9248              

Impacted Files	Coverage Δ
moveit_ros/moveit_servo/src/servo_parameters.cpp	69.48% <100.00%> (+0.33%)	⬆️

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