DEV: makes chat modals use the new <DModal /> component (#22495)

This commit also standardize the naming pattern of modals: `<Chat::Modal::FooBar />` and changes css class accordingly.

Co-authored-by: David Taylor <david@taylorhq.com>

app/assets/javascripts/select-kit/addon/components/select-kit.js

@@ -311,6 +311,7 @@ export default Component.extend(
       hiddenValues: null,
       disabled: false,
       expandedOnInsert: false,
+      formName: null,
     },
 
     autoFilterable: computed("content.[]", "selectKit.filter", function () {