When blank line is entered, CLI raises error

[wendytang]

Describe the bug When a blank line is entered in the CLI, an error arises:

( O)>
◓  Parsing possibilities...                                                                                                                                                2025-03-07T20:15:03.139647Z ERROR goose::agents::truncate: Error: Request failed: Request failed with status: 400 Bad Request. Message: {"external_model_provider":"amazon-bedrock","external_model_error":{"message":"Your API request included an `assistant` message in the final position, which would pre-fill the `assistant` response. When using tools, pre-filling the `assistant` response is not supported."}}

A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

1. goose session
2. Enter a blank line

Expected behavior Goose should not error but ask the user what they can help with

Please provide following information:

• OS & Arch: [e.g. mac m1 max]
• Interface: [CLI]
• Version: [latest]
• Extensions enabled: [none]
• Provider & Model: [claude sonnet 3.5]