[@mantine/dates] Fix esm mandatory file extensions bug

[BengtHagemeister]

When using @mantine/dates the following error throws:

Error: Cannot find module '/Users/user/code/node_modules/.pnpm/@mantine+dates@7.0.1_@mantine+core@7.0.1_@mantine+hooks@7.0.1_dayjs@1.11.10_react-dom@18.2.0_react@18.2.0/node_modules/dayjs/plugin/utc' imported from /Users/user/code/node_modules/.pnpm/@mantine+dates@7.0.1_@mantine+core@7.0.1_@mantine+hooks@7.0.1_dayjs@1.11.10_react-dom@18.2.0_react@18.2.0/node_modules/@mantine/dates/esm/utils/get-timezone-offset.mjs
Did you mean to import dayjs@1.11.10/node_modules/dayjs/plugin/utc.js?

This is because of the missing .js when bare importing the plugins.

See https://nodejs.org/api/esm.html#esm_mandatory_file_extensions

and iamkun/dayjs#1167 specifically iamkun/dayjs#1167 (comment)

[theajr]

@BengtHagemeister is there any other workaround without waiting for this PR to merge?

@rtivital Could you please review and merge or provide any possible solution?

P.S Out of curiosity - How samples are working on docs site?

[rtivital]

Thanks!