Fix mainfileinfodetailsview appending

Since the jquery update to 3.5.0, it seems Handlebars doesn't correctly
render self-closed elements. This fixes mainfileinfodetailsview template
to not use self-closed elements and fixes the JS unit tests.

Signed-off-by: Vincent Petry <vincent@nextcloud.com>
Signed-off-by: nextcloud-command <nextcloud-command@users.noreply.github.com>