Fix sporadic crash when launching GUI client on windows

[azeey]

🦟 Bug fix

Toward: #2945

Summary

The issues seems to stem form using iterators created on temporary std::string objects. Calling std::ostringstream::str creates a new string each time, so the begin and end calls are getting two different copies of the string. This PR instead just uses a single std::string object to construct the command line. This also wraps arguments with extra quotes if necessary. Lastly, it adds debug messages to help with QT6 library paths.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[j-rivero]

I've tested the PR, I still see some intermittent failures in running gz sim or gz-sim-main . Still need to debug them but I agree that the PR should help.