Wait and check for the grasp service

[yeshwanths88]

Description

#2064

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

[welcome]

Thanks for helping in improving MoveIt and open source robotics!

[codecov-io]

Codecov Report

Merging #2065 into master will increase coverage by 0.37%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #2065      +/-   ##
==========================================
+ Coverage   54.16%   54.54%   +0.37%     
==========================================
  Files         328      328              
  Lines       25624    25624              
==========================================
+ Hits        13880    13977      +97     
+ Misses      11744    11647      -97     

Impacted Files	Coverage Δ
.../move_group_interface/src/move_group_interface.cpp	40.77% <0.00%> (+3.66%)	⬆️
...ove_group_interface/src/wrap_python_move_group.cpp	43.03% <0.00%> (+11.07%)	⬆️
...s/include/moveit/py_bindings_tools/serialize_msg.h	80.00% <0.00%> (+80.00%)	⬆️
.../include/moveit/py_bindings_tools/py_conversions.h	86.66% <0.00%> (+86.66%)	⬆️
...ls/include/moveit/py_bindings_tools/gil_releaser.h	100.00% <0.00%> (+100.00%)	⬆️

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[tylerjw]

Thank you for this change. It is always easy to review small changes.

[tylerjw]

How did you pick this duration for the wait? Should it not just be 0 to make it fail right away if the service is not available?

[v4hn]

Suggested change

	if (!plan_grasps_service_.waitForExistence(ros::Duration(0.2)))
	if (!plan_grasps_service_.exists())

[v4hn]

Thank you for your contribution @yeshwanths88 .

#2077 supersedes this request and includes this commit and more improvements.