feat: add back template id field for create agent req (#2300)

Co-authored-by: Caren Thomas <caren@caren-mac.local>
Co-authored-by: Sarah Wooders <sarahwooders@gmail.com>

letta/schemas/agent.py

@@ -118,6 +118,7 @@ class CreateAgent(BaseModel, validate_assignment=True):  #
     )
     context_window_limit: Optional[int] = Field(None, description="The context window limit used by the agent.")
     embedding_chunk_size: Optional[int] = Field(DEFAULT_EMBEDDING_CHUNK_SIZE, description="The embedding chunk size used by the agent.")
+    from_template: Optional[str] = Field(None, description="The template id used to configure the agent")
 
     @field_validator("name")
     @classmethod