Remove unneeded "tab" CSS class from chat view
Remove unneeded "tab" CSS class from chat view

The "tab" CSS class does not apply when the chat view is shown in the
main view, and it is not needed either when shown in the sidebar, as it
is automatically set in the div to which the view is appended (in fact,
it was a bug, as two "tab" classes were nested and thus its padding was
duplicated).

Signed-off-by: Daniel Calviño Sánchez <bd7629e975cc0e00ea7cda4ab6a120f2ee42ac1b@gmail.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed