fix(auth): guard None redirect_uris for pyright

Author: KirtiRamchandani

src/mcp/server/auth/handlers/register.py

@@ -91,7 +91,17 @@ async def handle(self, request: Request) -> Response:
                 status_code=400,
             )
 
-        for redirect_uri in client_metadata.redirect_uris:
+        redirect_uris = client_metadata.redirect_uris
+        if redirect_uris is None:
+            return PydanticJSONResponse(
+                content=RegistrationErrorResponse(
+                    error="invalid_client_metadata",
+                    error_description="redirect_uris is required",
+                ),
+                status_code=400,
+            )
+
+        for redirect_uri in redirect_uris:
             try:
                 validate_registered_redirect_uri(redirect_uri)
             except ValueError as error: