Removing topic name parameter configuration and replacing with const strings

[Gaurang-1402]

Description

This PR introduces changes to streamline the setup process for the moveit_cpp::PlanningSceneMonitorOptions and moveit_servo::ServoParameters by utilizing constant strings for topic names instead of parameter-based configurations. The changes ensure that topic names are now consistent and predefined. This modification also implies that users who need customized topic names will now have to use topic remapping in their launch files or at the ROS node level.

These updates are in direct response to the issue discussed in #2714

Checklist

• [x] Required by CI: Code is auto formatted using clang-format
• [ ] Extend the tutorials / documentation reference In the tutorials, I see some files where changes need to be made to remove topic names from parameters, for example here:  https://github.com/ros-planning/moveit2_tutorials/blob/main/doc/examples/moveit_cpp/config/moveit_cpp.yaml I'm confused about the sequence of changes though since these are 2 separate repos. Do I make these changes before this PR is merged, do I make 2 simultaneous PR or do I raise an issue on that repo? Some guidance would be helpful to proceed on this point.
• [x] Document API changes relevant to the user in the MIGRATION.md notes Done included in the commit
• [ ] Create tests, which fail without this PR reference As this PR stands, there are no scenarios where the code fails without this PR because it is an API enhancement. Yet, if needed, I can create tests- please let me know.
• [ ] Include a screenshot if changing a GUI Not Applicable
• [x] While waiting for someone to review your request, please help review another open pull request to support the maintainers

[mergify[bot]]

Please target the main branch for development, we will backport the changes to humble for you if approved and if they don't break API.

[github-actions[bot]]

This PR is stale because it has been open for 45 days with no activity. Please tag a maintainer for help on completing this PR, or close it if you think it has become obsolete.

[henningkayser]

@Gaurang-1402 what's the current status of this PR? It would also be great if you could target the 'main' branch. We can backport fixes and non-breaking changes to 'humble'