Update index js

[sdadn]

Summary

This PR continues the work in https://github.com/cerner/terra-graphs/pull/332 by updating index.js to also import the css. Now, css no longer has to be explicitly imported when consuming graphs.

Before:

import Carbon from '@cerner/carbon-graphs';
import '@cerner/carbon-graphs/dist/css/carbon-graphs.css';

After

import Carbon from '@cerner/carbon-graphs';

Testing

This change was tested using:

• [x] WDIO
• [ ] Jest
• [ ] Visual testing (please attach a screenshot or recording)
• [ ] Other (please describe below)
• [ ] No tests are needed

This was tested by ensuring there are no css changes in screenshots. Removing the css import causes the css to break, which confirms that this change works.

Reviews

In addition to engineering reviews, this PR needs:

• [ ] UX review
• [ ] Accessibility review
• [ ] Functional review

Additional Details

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Thank you for contributing to Terra. @cerner/terra

[github-actions[bot]]

	Fails
:no_entry_sign:	Please include a CHANGELOG entry for each changed package this PR. Looks like a CHANGELOG entry is missing for: - carbon-graphs - terra-graphs-docs

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