Bump google-genai to 1.55 (#3727)

Author: dsfaccini

pydantic_ai_slim/pyproject.toml

@@ -70,7 +70,7 @@ logfire = ["logfire[httpx]>=4.16.0"]
 openai = ["openai>=2.11.0"]
 cohere = ["cohere>=5.18.0; platform_system != 'Emscripten'"]
 vertexai = ["google-auth>=2.36.0", "requests>=2.32.2"]
-google = ["google-genai>=1.51.0"]
+google = ["google-genai>=1.55.0"]
 anthropic = ["anthropic>=0.75.0"]
 groq = ["groq>=0.25.0"]
 openrouter = ["openai>=2.8.0"]