fix(IURLGenerator): Allow markdown parenthesis in URL_REGEX_NO_MODIFIERS

[provokateurin]

Summary

Related to nextcloud/spreed#13756.
Apparently the web UI doesn't use this regex but a hardcoded one, but I fixed it there as well: nextcloud-libraries/nextcloud-vue#6224
Clients should be using this regex, so it also needs to work with the parenthesis from embedded markdown links.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[nickvergessen]

This needs extensive tests added to not break cases like:

Please check the website (https://nextcloud.com/)

Please check the website https://nextcloud.com/wikipedia_(has-braces)

And the likes. It was a long fight with usability of most users. So we really prefer broken previews over broken UX of normal users posting behaviour

[provokateurin]

If a URL has special characters, they must be encoded, no? I don't see how even the browser could work with it, if the URL is not encoded.