Make sure "new label" button is always visible even when labels panel has scrollbar

[somebody1234]

Pull Request Description

• Move "new label" button outside of scroll container so that it is always visible

Important Notes

None

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  TypeScript,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• Unit tests have been written where possible.
• If meaningful changes were made to logic or tests affecting Enso Cloud integration in the libraries,
  or the Snowflake database integration, a run of the Extra Tests has been scheduled.
  • If applicable, it is suggested to paste a link to a successful run of the Extra Tests.