Fix: Update RSC config references in server_rendering_js_code.rb

Critical bugfix discovered during code review:
- Lines 67-68 were still calling ReactOnRails.configuration instead of ReactOnRailsPro.configuration
- Updated to use ReactOnRailsPro.configuration.react_client_manifest_file
- Updated to use ReactOnRailsPro.configuration.react_server_client_manifest_file
- Extracted config to local variable to fix RuboCop line length violation

This ensures RSC manifest file configurations are read from the correct Pro configuration
after they were moved from open-source to Pro gem in Phase 2.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: AbanoubGhadban

react_on_rails_pro/lib/react_on_rails_pro/server_rendering_js_code.rb

@@ -64,8 +64,9 @@ def render(props_string, rails_context, redux_stores, react_component_name, rend
             "'serverRenderReactComponent'"
           end
         rsc_params = if ReactOnRailsPro.configuration.enable_rsc_support && render_options.streaming?
-                       react_client_manifest_file = ReactOnRails.configuration.react_client_manifest_file
-                       react_server_client_manifest_file = ReactOnRails.configuration.react_server_client_manifest_file
+                       config = ReactOnRailsPro.configuration
+                       react_client_manifest_file = config.react_client_manifest_file
+                       react_server_client_manifest_file = config.react_server_client_manifest_file
                        <<-JS
                           railsContext.reactClientManifestFileName = '#{react_client_manifest_file}';
                           railsContext.reactServerClientManifestFileName = '#{react_server_client_manifest_file}';