fix(core/select): handle overflow of pills

[goncalosard]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (yarn build) was run locally and any changes were pushed
• Unit tests (yarn test) were run locally and passed
• Visual Regression Tests (yarn visual-regression) were run locally and passed
• Linting (npm lint) was run locally and passed

Pull request type

Please check the type of change your PR introduces:

• Bug fix
• Feature
• Refactoring (no functional changes, no API changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

GitHub Issue Number: #124

What is the new behavior?

No longer has pill overflow and the input adapts to how many pills are there. If no longer has space, it goes below the pills.

Does this introduce a breaking change?

• Yes
• No

Testing

Tested locally

[nuke-ellington]

The pills and the input should be on the same "line" if possible. No line break in between. Also no more than two rows at a time may be shown. Scrollbar should handle the vertical overflow. When in doubt category filter has the desired behaviour as ref.

[danielleroux]

• visual regression test is missing