Remove references to deprecated Import model (#31759)

app/views/settings/imports/index.html.haml

@@ -23,7 +23,7 @@
       = f.input :mode,
                 as: :radio_buttons,
                 collection_wrapper_tag: 'ul',
-                collection: Import::MODES,
+                collection: Form::Import::MODES,
                 item_wrapper_tag: 'li',
                 label_method: ->(mode) { safe_join([I18n.t("imports.modes.#{mode}"), content_tag(:span, I18n.t("imports.modes.#{mode}_long"), class: 'hint')]) }