Change zip code text field to enable selection and preserve contents on paste
Change zip code text field to enable selection and preserve contents on paste

One more step toward making the address fields behave like normal text fields.

I think the primary user benefit of the old behavior was being able to paste into a
partially filled field, and have the old contents completely replaced by the pasteboard
contents.

I'm not convinced that's always what they want, and I think the upcoming support for
`textContentType` will replace copy/paste as the easiest & best way to enter addresses.
This also enables users to move the insertion point and more easily fix errors.

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