feat: check and apply markdown for smart picker output

[luka-nextcloud]

📝 Summary

• Resolves: Support for Markdown in Text templates #4784

Always consider smart picker output as markdown.

🚧 TODO

• ...

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

[juliushaertl]

A few suggestions for detecting the markdown syntax (I know we can't cover everything there), but otherwise this seems fine and works well 👍

[mejo-]

Maybe I'm missing something here, but why do we have to detect markdown manually at all, instead of just doing isValidMarkdown() and always sending the content through markdownit.render() if that succeeds?

[juliushaertl]

Hm, unsure about that. It might be fine to just always pass it to markdown it indeed.

[luka-nextcloud]

I have tried this way and faced an issue. The markdown-it render function always adds some newline character to content. So, If input value is an url, the inserted content will be a normal string instead of a link (enclose it in an angle brackets).