Tweak the react-select custom components

[bl-nero]

Fixes #47823

This PR does two things:

• Fixes the bug where clicking the remove icon on a value causes the dropdown to open (see the attached bug). It does so by delegating common styling and event handling logic to default react-select components instead of attempting to do everything on our own. This also means moving some padding handling from components themselves to the wrapper stylesheet.
• It tweaks the multi-value pills to make sure that there's equal amount of space around these when the component goes multiline.

[bl-nero]

Tested manually by inspecting a random handful of drop-downs throughout the app.

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