Spring-ai Add Anthropic PDF Multimodal Support

• Enhance AnthropicChatModel to support PDF and document content types
• Introduce getContentBlockTypeByMedia method for flexible media type handling
• Update ContentBlock handling to dynamically determine content type for media
• Add multimodal PDF support test case for Claude 3.5 Sonnet
• Update documentation to reflect PDF and multimodal capabilities
• Modify comparison chart to show PDF support for Anthropic Claude

Release #1819

Comment From: markpollack

updated to throw exception if mime type is not know.

merged in e543cd082d86dfb71702924bcff56e16621d1eb4