Change the docstring for the transfer_to_agent tool to remove unneeded information sent to the model.

[slilichenko]

The tool's docstring includes notes to developers. This docstring is sent on every invocation to the model, consuming input tokens and increasing chances of hallucinations. Example of the tool description sent to the model:

description: "Transfer the question to another agent. This tool hands off control to another agent when it's more suitable to answer the user's question according to the agent's description. Note: For most use cases, you should use TransferToAgentTool instead of this function directly. TransferToAgentTool provides additional enum constraints that prevent LLMs from hallucinating invalid agent names. Args: agent_name: the agent name to transfer to. "
name: "transfer_to_agent"