Classes added to form container template causing issues

[ag-tim]

From the comment in "https://github.com/phase2/particle/blob/master/apps/drupal/templates/form/container.html.twig" it sounds like the two classes were added to this override template for purposes of the site search form. The 'mx-sm-3' class in particular is causing problems because this template is called in many places, some of which are not even forms. Adding spacing to all of these different places that the template is used is, I think, too broad a brush and they should probably be removed from the template and added differently for the site search case.
It's a pretty simple fix, I'm just not sure what other issues changing it may cause.

Drupal admin toolbar:
BEGIN OUTPUT from 'core/themes/stable/templates/form/container.html.twig
div class="toolbar-menu-administration

From views:
BEGIN OUTPUT from 'core/themes/stable/templates/form/container.html.twig
div class="views-element-container"