fix(segmented-button): move types and validSizes to marko file

[LuLaValva]

Description

• Move types and validSizes to the .marko file from component.ts

[changeset-bot]

🦋 Changeset detected

Latest commit: 859f89a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@ebay/ebayui-core	Patch

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[agliga]

Do we really need all these changes?I thought we just need to change the import
Also, can we verify with Dylan that it's OK to import the template from the component?

[LuLaValva]

Since we moved validSizes into the .marko file it made sense to also move the TypeScript interfaces (especially for consistency with other components that do the same thing). Without changing the validSizes from static to export, this is also the only place that we can access its type now.