fix(theme): added a workaround so that defaultProps are also picked up from MUI v5 components (like Button disabledRipple or Grid spacing)

[christoph-jerolimov]

Hey, I just made a Pull Request!

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or Updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)

[rhdh-gh-app]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
@red-hat-developer-hub/backstage-plugin-theme	workspaces/theme/plugins/theme	patch	v0.4.7

[ciiay]

/lgtm

I wasn't able to reproduce the issue, but verified this solution doesn't break anything in local showcase 👍 Let's test out when the new version is out.