fix: Add banner_url to MicrodaoDetail response

- Add missing banner_url field when creating MicrodaoDetail
- This fixes issue where banner_url was saved in DB but not returned by /api/microdao/{slug} endpoint

services/city-service/routes_city.py

@@ -3095,6 +3095,7 @@ async def get_microdao_by_slug(slug: str):
             parent_microdao_slug=dao.get("parent_microdao_slug"),
             child_microdaos=child_microdaos,
             logo_url=dao.get("logo_url"),
+            banner_url=dao.get("banner_url"),
             agents=agents,
             channels=channels,
             public_citizens=public_citizens,