Revert changes to how the notes are paginated in the API

lib/api/notes.rb

@@ -22,11 +22,17 @@ module API
           @noteable = user_project.send(:"#{noteables_str}").find(params[:"#{noteable_id_str}"])
           # We exclude notes that are cross-references and that cannot be viewed
-          # by the current user.
+          # by the current user. By doing this exclusion at this level and not
+          # at the DB query level (which we cannot in that case), the current
+          # page can have less elements than :per_page even if
+          # there's more than one page.
           notes =
-            @noteable.notes.
+            # paginate() only works with a relation. This could lead to a
+            # mismatch between the pagination headers info and the actual notes
+            # array returned, but this is really a edge-case.
+            paginate(@noteable.notes).
             reject { |n| n.cross_reference_not_visible_for?(current_user) }
-          present paginate(Kaminari.paginate_array(notes)), with: Entities::Note
+          present notes, with: Entities::Note
         end
         # Get a single +noteable+ note