PR Summary

I'd like to change various properties of an errorplot using a Qt figureoptions dialogue. This dialog is presented when NavToolBar is created. At the moment errorplots do not show up in the Curves tab, so one can't change their colour, markersize, etc.
This PR detects if an ErrorbarCollection is present, and adds it to the Curves popup list. This permits adjustment of the line/marker properties of the 'host' Line. Pragmatically the bars/caps of the errorplot are set to be the same color as the host Line, and the same linewidth of the host Line.

fixes #18631

PR Checklist

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (run flake8 on changed files to check).
• New features are documented, with examples if plot related.
• [N/A] Documentation is sphinx and numpydoc compliant (the docs should build without error).
• [N/A] Conforms to Matplotlib style conventions (install flake8-docstrings and pydocstyle<4 and run flake8 --docstring-convention=all).
• New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
• [N/A] API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).