Add Storybook snapshot testing

**Is your feature request related to a problem or planned work?**
No

**Describe the solution you'd like and scope of work**
Add support for snapshot testing to the existing Storybook setup for both the UI and widgets library. Should be limited to a config setup for each library and validating the tests work.

https://storybook.js.org/docs/writing-tests/storyshots-migration-guide

Start by locating the existing Storybook configurations for the UI and widgets libraries. Read the linked Storybook snapshot-testing migration guide, add the corresponding configuration for each library, and verify that snapshot tests run successfully for both.

Written by the indexing model from the issue text.