Optimize `left`, `right` to avoid copying for `Utf8`, `LargeUtf8` input

[neilconway]

Is your feature request related to a problem or challenge?

We currently avoid copying for Utf8View input, but we always copy for other string input types. If we changed left and right to always return Utf8View (a la substr), we could be zero-copy for the other string input types as well.

Describe the solution you'd like

No response

Describe alternatives you've considered

No response

Additional context

No response

[neilconway]

take