Explicit convert from std::filesystem::path to std::string for Windows compatibility (backport #3249)

[mergify]

Description

On Linux and macOS std::filesystem::path is implicitly convertible to std::string, while on Windows it is convertible to std::wstring, see https://en.cppreference.com/w/cpp/filesystem/path and https://stackoverflow.com/questions/57377349/implicit-conversion-between-stdfilesystempath-and-stdstring-should-it-hap . If we want to convert std::filesystem::path to std::string in a Windows-compatible way, it is then necessary to explicitly call the .string() method.

Fix part of #2391 .

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

---

This is an automatic backport of pull request #3249 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 2b9173b has failed:

On branch mergify/bp/humble/pr-3249
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit 2b9173b37.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   moveit_setup_assistant/moveit_setup_assistant/src/collisions_updater.cpp
	modified:   moveit_setup_assistant/moveit_setup_core_plugins/include/moveit_setup_core_plugins/configuration_files.hpp
	modified:   moveit_setup_assistant/moveit_setup_core_plugins/src/configuration_files_widget.cpp
	modified:   moveit_setup_assistant/moveit_setup_core_plugins/src/start_screen.cpp
	modified:   moveit_setup_assistant/moveit_setup_core_plugins/src/start_screen_widget.cpp
	modified:   moveit_setup_assistant/moveit_setup_framework/include/moveit_setup_framework/data/srdf_config.hpp
	modified:   moveit_setup_assistant/moveit_setup_framework/src/srdf_config.cpp
	modified:   moveit_setup_assistant/moveit_setup_framework/src/utilities.cpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   moveit_setup_assistant/moveit_setup_assistant/src/setup_assistant_widget.cpp
	both modified:   moveit_setup_assistant/moveit_setup_framework/src/urdf_config.cpp

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 75.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 51.40%. Comparing base (c705c2c) to head (a67c37b).
Report is 1 commits behind head on humble.

Files with missing lines	Patch %	Lines
...sistant/moveit_setup_framework/src/urdf_config.cpp	66.67%	3 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##           humble    #3253      +/-   ##
==========================================
+ Coverage   51.40%   51.40%   +0.01%     
==========================================
  Files         382      382              
  Lines       31893    31896       +3     
==========================================
+ Hits        16392    16394       +2     
- Misses      15501    15502       +1     

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