Remove simplify_nullable_unions - Google supports type: 'null' natively

The November 2025 announcement explicitly states that Google now supports
'type: null' in JSON schemas, so we don't need to convert anyOf with null
to the OpenAPI 3.0 'nullable: true' format.

Keep __init__ method for documentation purposes to explicitly note why
we're using the defaults (native support for $ref and type: null).

Addresses reviewer question: "Do we still need simplify_nullable_unions?
type: 'null' is now supported natively"

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: conradlee

pydantic_ai_slim/pydantic_ai/profiles/google.py

@@ -22,6 +22,11 @@ class GoogleJsonSchemaTransformer(JsonSchemaTransformer):
     Gemini supports [a subset of OpenAPI v3.0.3](https://ai.google.dev/gemini-api/docs/function-calling#function_declarations).
     """
 
+    def __init__(self, schema: JsonSchema, *, strict: bool | None = None):
+        # prefer_inlined_defs defaults to False (native $ref/$defs support)
+        # simplify_nullable_unions defaults to False (Google now supports type: 'null' natively per Nov 2025 announcement)
+        super().__init__(schema, strict=strict)
+
     def transform(self, schema: JsonSchema) -> JsonSchema:
         # Remove properties not supported by Gemini
         schema.pop('$schema', None)