Fix duplicate rake task execution by removing explicit task loading

Rails Engine automatically loads all .rake files from lib/tasks/ directory
via its run_tasks_blocks method. The explicit load calls in the rake_tasks
block caused each task file to be loaded twice:
1. Once via explicit load in rake_tasks block (Railtie layer)
2. Once via automatic loading by Rails::Engine

This resulted in tasks having duplicate action blocks, causing:
- react_on_rails:assets:webpack to run webpack build twice
- react_on_rails:generate_packs to run twice
- react_on_rails:locale to compile locales twice

The fix removes the explicit load calls and relies on Rails Engine's
standard auto-loading behavior from lib/tasks/*.rake, which already
works correctly for doctor.rake.

Verified that all tasks (assets:webpack, generate_packs, locale, doctor)
load correctly with exactly 1 action block each.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

lib/react_on_rails/engine.rb

@@ -83,10 +83,7 @@ def self.package_json_missing?
       ReactOnRails::ServerRenderingPool.reset_pool
     end
 
-    rake_tasks do
-      load File.expand_path("../tasks/generate_packs.rake", __dir__)
-      load File.expand_path("../tasks/assets.rake", __dir__)
-      load File.expand_path("../tasks/locale.rake", __dir__)
-    end
+    # Rake tasks are automatically loaded from lib/tasks/*.rake by Rails::Engine
+    # No need to explicitly load them here to avoid duplicate loading
   end
 end