fix: help mypy & fix precommit on main

Add type to help mypy figure out.

Signed-off-by: Sébastien Han <seb@redhat.com>

src/llama_stack/providers/inline/agents/meta_reference/agent_instance.py

@@ -1015,7 +1015,7 @@ async def load_data_from_url(url: str) -> str:
     if url.startswith("http"):
         async with httpx.AsyncClient() as client:
             r = await client.get(url)
-            resp = r.text
+            resp: str = r.text
             return resp
     raise ValueError(f"Unexpected URL: {type(url)}")