[#1807] Added ThemeProvider for tests

[smitbarmase]

Fixes #1807

Using styled-components and function like prop from theme.js, was failing tests as we haven't wrapped the render function from @testing-library in test-utils.js.

I added ThemeProvider and provided the default theme light to it for testing. Similar to I18nextProvider is already wrapping it to provide default translation.

I have verified that this pull request:

• has no linting errors (npm run lint)
• is from a uniquely-named feature branch and has been rebased on top of the latest develop branch. (If I was asked to make more changes, I have made sure to rebase onto develop then too)
• is descriptively named and links to an issue number, i.e. Fixes #123

[release-com]

Release Environments

p5.js-web-editor
app-ted9fd7-p5-js-web-editor.releaseapp.io

[catarak]

Oh awesome! Thanks for working on this.