Fixes #25142 - fix extending module_streams api docs

`update_api` is only usable from within a concern. When extending an API
inside controller that's coming from concern, `apipie_update_params` should be
used instead.

Also, there has been an issue on apipie side, that prevented merging top-level
params (see Apipie/apipie-rails#642).

Both changes are needed in order for this issue to be resolved.

app/controllers/katello/api/v2/module_streams_controller.rb

@@ -6,7 +6,8 @@ class Api::V2::ModuleStreamsController < Api::V2::ApiController
 
     before_action :check_params, :only => :index
 
-    update_api(:index) do
+    # updating params inherited from Katello::Concerns::Api::V2::RepositoryContentController
+    apipie_update_params([:index]) do
       param :host_ids, Array, :desc => N_("List of host id to list available module streams for")
       param :name_stream_only, :boolean, :desc => N_("Return name and stream information only)")
     end