Bump ejs and @storybook/react in /ui

Removes [ejs](https://github.com/mde/ejs). It's no longer used after updating ancestor dependency [@storybook/react](https://github.com/storybookjs/storybook/tree/HEAD/app/react). These dependencies need to be updated together.


Removes `ejs`

Updates `@storybook/react` from 5.2.6 to 6.5.12
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/v6.5.12/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v6.5.12/app/react)

---
updated-dependencies:
- dependency-name: ejs
  dependency-type: indirect
- dependency-name: "@storybook/react"
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]