src: change GetStringWidth's expand_emoji_sequence option default

The option is now set to true by default. Most terminals do not have
full emoji support and visualize emojis with zero width joiners as
individual emojis.
Also verify that at least one argument is always passed through to the
function and remove support for passing through code points. Only
accept strings from now on to simplify the API.

PR-URL: https://github.com/nodejs/node/pull/31112


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>