Reset connection_without_retries in streaming tests

The mock_request_and_response method was only resetting @connection
but not @connection_without_retries. This caused tests to use a cached
connection instead of the mocked one, leading to actual component
rendering instead of using the mocked streaming response.

This fix ensures both connection instance variables are reset to nil
before each test, allowing the mock to work correctly.

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

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

Author: justin808

react_on_rails_pro/spec/dummy/spec/helpers/react_on_rails_pro_helper_spec.rb

@@ -330,6 +330,7 @@ def response; end
     def mock_request_and_response(mock_chunks = chunks, count: 1)
       # Reset connection instance variables to ensure clean state for tests
       ReactOnRailsPro::Request.instance_variable_set(:@connection, nil)
+      ReactOnRailsPro::Request.instance_variable_set(:@connection_without_retries, nil)
       original_httpx_plugin = HTTPX.method(:plugin)
       allow(HTTPX).to receive(:plugin) do |*args|
         original_httpx_plugin.call(:mock_stream).plugin(*args)