Search for Unsplash photos Args: query: Search keyword page: Page number (1-based) per_page: Results per page (1-30) order_by: Sort method (relevant or latest) color: Color filter (black_and_white, black, white, yellow, orange, red, purple, magenta, green, teal, blue) orientation: Orientation filter (landscape, portrait, squarish) Returns: List[UnsplashPhoto]: List of search results containing photo objects with the following properties: - id: Unique identifier for the photo - description: Optional text description of the photo - urls: Dictionary of available image URLs in different sizes - width: Original image width in pixels - height: Original image height in pixels