Add license SPDX ID to babel preset

[jstvz]

The current value is being flagged by static analysis tools in downstream projects.

Fixes #

Additional description

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REVIEWER checklist (do not remove)

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• [ ] Tests have been added for new props to prevent regressions in the future. See readme.
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• [ ] Review tests are passing in the browser. Open http://localhost:8001/.
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  Required only if there are markup / UX changes

• [ ] Add year-first date and commit SHA to last-slds-markup-review in package.json and push.
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• [ ] Add year-first review date, and commit SHA, last-accessibility-review, to package.json and push.
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[interactivellama]

@jstvz Does this update need a release to NPM or is having it present in the repo enough?

[jstvz]

@interactivellama My understanding is that it'll need a release to NPM to get picked up by Nexus.