This commit adds a wrapper around the "dropdown_widget" of
"dropdown_widget_label".
This wrapper is primarily added so as to be able to show tippy
tooltips over the dropdowns in case they are disabled, since
we can not assign tippy instances to disabled buttons.
We now use "settings-field-label" and "modal-field-label"
class on label elements in settings and modals respectively
to add the bottom margin which was previously done by
"dropdown-title" class as it is better to have more
generic names to use on label for all type of inputs.