[BUG] Underscores in Contenttypes cause issues with relations

[maximilianredt]

If a Contenttype uses an underscore (e.g. pages_en) this will cause issues with relations, because in Bolt\Legacy\Storage::getRelation() instead of the tablename the slug is being used. For contenttypes with an underscore this by default gets replaced by a dash.

Bolt Version: 3.2.2

Possible solution:
Change
$contenttype = $content[util::array_first_key($content)]->contenttype['slug']
to
$contenttype = $content[util::array_first_key($content)]->contenttype['tablename']