FEATURE: Add attribution to staff notice and rename functionality (#30920)

The name "Staff Notice" was not quite right since TL4 users
can also add these notices. This commit changes the wording to
"Official Notice".

In addition to this, currently you have to go look into the staff
action logs to see who is responsible for a notice. This commit
stores the ID of the user who created the notice, then shows this
information on each notice to staff users.

Finally, I migrated the ChangePostNoticeModal component to gjs.

spec/requests/api/posts_spec.rb

@@ -595,6 +595,9 @@ RSpec.describe "posts" do
                  notice: {
                    type: :object,
                  },
+                 notice_created_by_user: {
+                   type: %i[object null],
+                 },
                  reviewable_id: {
                    type: %i[integer null],
                  },