Checkbox, Radio: fix slotted text not wrapping

[RasmusKjeldgaard]

Which issue does this PR close?

This PR closes #3648

What is the new behavior?

Adding text in the default slot of checkbox or radio will now wrap, similar to how it does for text set with the text-property. The white-space style declaration is moved to the label-text-wrapper part as it is used for both types of text.

Does this PR introduce a breaking change?

• [ ] Yes
• [x] No

Checklist:

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When the pull request has been approved it will be merged to develop by Team Kirby.

[RasmusKjeldgaard]

What is the reason for not letting the label text flow and wrap naturally - equivalent to white-space: normal (initial value)?

Excellent question! I forgot to mention it in the PR description, sorry! It is to preserve the functionality for creating line-breaks when text is supplied via the text property. So definitely something we should look into removing down the line, now that content can be slotted instead of supplied as a property.