lpad, rpad, translate should use codepoints, not graphemes

[neilconway]

Describe the bug

For consistency with most other SQL implementations (including Postgres), as well as the rest of DataFusion, lpad, rpad, and translate should use codepoints when manipulating Unicode strings, not graphemes. #3054 switched to using codepoints instead of graphemes in most places, but AFAICS the same should be done for these remaining UDFs.

To Reproduce

No response

Expected behavior

No response

Additional context

No response

[neilconway]

take

[neilconway]

@Dandandan I realize it was a long time ago, but if there was a reason you chose to have lpad, rpad, and translate continue to consider graphemes instead of codepoints, please let me know 😊