chore: Migrate json field names to camelCase (3/n)

PiperOrigin-RevId: 758394880

src/google/adk/sessions/session.py

@@ -14,6 +14,7 @@
 
 from typing import Any
 
+from pydantic import alias_generators
 from pydantic import BaseModel
 from pydantic import ConfigDict
 from pydantic import Field
@@ -37,6 +38,8 @@ class Session(BaseModel):
   model_config = ConfigDict(
       extra='forbid',
       arbitrary_types_allowed=True,
+      alias_generator=alias_generators.to_camel,
+      populate_by_name=True,
   )
   """The pydantic model config."""