fix: html5 tag errors

[SebastianKrupinski]

Resolves: Client Issue

Summery

• Adds DOCTYPE to html wrapper to prevent libxml errors for html 5 tag "DOMDocument::loadHTML(): Tag figure invalid in Entity, line: 1"
• Adds limitation to prevent network access for DOMDocument

[ChristophWurst]

Looks good

Is only main affected by this or should it be backported to stable releases?

[SebastianKrupinski]

Looks good

Is only main affected by this or should it be backported to stable releases?

Yes I would back port it to all the versions that support NC30+

[SebastianKrupinski]

Looks good

Is only main affected by this or should it be backported to stable releases?

Wait that might not be possible, I made changes to that code block recently, I'll check how far back it went

[SebastianKrupinski]

Yes, we would need to backport this also...

#10477

[st3iny]

Not necessarily. The fix also makes sense on top of the state before your alternate format fix. Although, a manual backport will be necessary.

Ref https://github.com/nextcloud/mail/blob/3f821e38e37cda3c1ae165a141f1b38f62191fbe/lib/Service/MimeMessage.php

[st3iny]

/backport to stable4.2