Fix file structure path in design.md from google/ to googleadk/ (#166)

* Initial plan

* Fix file structure path from google/ to googleadk/ in design.md

Co-authored-by: JesuTerraz <96103167+JesuTerraz@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: JesuTerraz <96103167+JesuTerraz@users.noreply.github.com>

Author: Copilot

libraries/microsoft-agents-a365-tooling-extensions-googleadk/docs/design.md

@@ -73,7 +73,7 @@ server_info = McpToolset(
 ## File Structure
 
 ```
-microsoft_agents_a365/tooling/extensions/google/
+microsoft_agents_a365/tooling/extensions/googleadk/
 ├── __init__.py
 └── services/
     ├── __init__.py