Fix/GitHub copilot error handling 5845

[DOsinga]

Summary

Fixes #5845

replaces: #6212

[Copilot]

Pull request overview

This PR fixes GitHub Copilot provider becoming unresponsive (issue #5845) by preventing images from being included in non-user messages, which causes provider errors. The fix adds filtering logic to ensure images are only sent in user messages, preventing the "image urls not allowed in non-user messages" error that was causing Goose to hang.

Changes:

• Modified image path detection to only apply to user messages (prevents assistant messages from accidentally loading images when mentioning file paths)
• Added filtering for explicit MessageContent::Image in non-user messages, replacing them with placeholder text
• Added comprehensive tests for both filtering scenarios

Comments suppressed due to low confidence (1)

crates/goose/src/providers/formats/openai.rs:90

• The PR description mentions "Added proper HTTP status code checking before processing streaming responses, error response parsing, and empty response detection" in githubcopilot.rs, but this change is not present in the diff. The only changes are the image filtering logic in this file. Either the PR description is outdated or the streaming error handling changes are missing from this PR.

                        // Extracting images from text is an outdated hack that should never
                        // be randomly applied to assistant messages
                        if message.role == Role::User {
                            if let Some(image_path) = detect_image_path(&text.text) {
                                if let Ok(image) = load_image_file(image_path) {
                                    content_array.push(json!({"type": "text", "text": text.text}));
                                    content_array.push(convert_image(&image, image_format));
                                } else {
                                    text_array.push(text.text.clone());
                                }
                            } else {
                                text_array.push(text.text.clone());
                            }
                        } else {
                            text_array.push(text.text.clone());
                        }