test(interactions): align openapi compliance with upstream rename outputs->steps

Google updated their Interactions OpenAPI spec
(https://ai.google.dev/static/api/interactions.openapi.json), removing
the readOnly 'outputs' property from CreateModelInteractionParams in
favor of 'steps' (a polymorphic transcript array). The compliance test
fetches the live spec, so it began failing on every PR once the spec
flipped over. Update the asserted output-field list to match.

Note: this only re-aligns the spec-shape assertion. Our SDK response
types (litellm/types/interactions/generated.py) still expose 'outputs'
and need to be regenerated separately to add 'steps'/Step variants and
decide on a back-compat path for callers reading .outputs.

tests/test_litellm/interactions/test_openapi_compliance.py

@@ -157,14 +157,15 @@ class TestResponseCompliance:
         # Check CreateModelInteractionParams which includes output fields
         schema = spec_dict["components"]["schemas"]["CreateModelInteractionParams"]
 
-        # Output fields (readOnly)
+        # Output fields (readOnly). Google renamed `outputs` → `steps` in the
+        # upstream spec; keep this list aligned with the live schema.
         output_fields = [
             "id",
             "status",
             "created",
             "updated",
             "role",
-            "outputs",
+            "steps",
             "usage",
         ]