Add polyfill for grapheme_levenshtein

[stof]

This polyfill should be implemented in 2 places:

• in symfony/polyfill-intl-grapheme
• in symfony/polyfill-php85, only when the intl extension is loaded (to cover the case of using intl on older PHP versions that won't have this function)

[sudam802]

May I work on this

[stof]

sure. Contributions are welcome.

[sudam802]

Do I need to folk the and setup the the whole symfony repo or just the polyfill will do? cause I saw the documentation says to folk the entire repo

[sudam802]

I added the function but something wrong with the test could you please guide me @stof