fix: Theme.name does not match registered name (#6186)

[derwehr]

The basics

• I branched from develop
• My pull request is against develop
• My code follows the style guide
• I ran npm run format and npm run lint

The details

Resolves

#6186

Proposed Changes

Add a line in defineTheme to convert its name to lower case.

Behavior Before Change

Theme.name did not match registered name, when it included upper case letters.

Behavior After Change

Now it does 🎉

[cpcallen]

Thanks for this fix. I added a question to the issue, but that is not why I have not merged this yet.

Rather, we're wondering if you would write a unit test for this change. This would be especially helpful at the moment as we're busy migrating core/ to TypeScript in the ts/migration branch, and we want to make sure this change doesn't get lost when that branch gets merged into develop. A unit test—safely outside the core/ directory, would catch such an inadvertent regression.

[derwehr]

Thanks for the review. I added a test for defineTheme normalizing to lowercase.

[BeksOmega]

Looks perfect! Thank you again for the contribution @derwehr :D