Ignore `encryption_enabled_by_default_for_room_type` for notices room

[MatMaul]

Currently the created rooms are encrypted, but the sent notices there are unencrypted which is rather ugly.

My assumptions were wrong so this PR got fully rewrote.

It now bypasses encryption_enabled_by_default_for_room_type setting when creating server notices room, since the notices will be send unencrypted anyway.

Signed-off-by: Mathieu Velten matmaul@gmail.com

Pull Request Checklist

• [x] Pull request is based on the develop branch
• [x] Pull request includes a changelog file.
• [x] Pull request includes a sign off
• [x] Code style is correct (run the linters)

[MatMaul]

Sorry for the force push, this got fully rewrote following wrong assumptions.