Fix tabs toolbar content alignment

[atmgrifter00]

Pull Request

🤨 Rationale

SLE bug: Nimble | nimble-tabs-toolbar | alignment of the child elements has been altered.

👩‍💻 Implementation

Just added styling that will expand the end slot to fill the rest of the space of the Tabs width.

🧪 Testing

There is a Chromatic test in place that is already checking this case, but I must have glossed over that change when examining it for the scrollable tabs submission.

✅ Checklist

• [x] I have updated the project documentation to reflect my changes or determined no changes are needed.

[rajsite]

Bypassing Jesse and marking autocomplete for trivial change and updated stories look good