How do I remove the Speedwell theme from Liferay DXP 7.3?

Issue

• When not using Liferay Commerce in a DXP 7.3 environment, the Speedwell theme may remain as the default fall back theme when deploying a custom theme, but it may not work correctly when not using Commerce

Environment

• Liferay DXP 7.3

Resolution

• The theme is stored in the Commerce LPKG files in the /osgi/marketplace directory: if you open the Liferay Commerce - Liferay Commerce - Impl.lpkg file in an Archive Manager you'll find the .WAR file for the theme inside.
• If you're not using Commerce and do not plan to use it in your DXP 7.3 environment, it is better to remove both Commerce LPKG files (both the Impl and the API files) entirely rather than removing the theme's .WAR file only. This should ideally be done with Liferay shut down.
• You will additionally want to clear the /osgi/state folder to avoid some FileNotFoundExceptions for these LPKG files during startup.