feat: enhanced multimodal error handling with verbose mode for blob image functions

[shuoweil]

Here are the changes:

1. Added bool type support
2. Added verbose parameter to all blob functions - When verbose=True, functions return a structured response with both status (error messages) and content fields. When verbose=False, they return only the content
3. Enhanced error handling - All functions now wrap their core logic in try-catch blocks and return structured error information.
4. Updated return types - Functions that previously returned bytes now return str (base64-encoded) to support the structured JSON response format.
5. Updated API interfaces - All blob accessor methods (exif, image_blur, image_resize, image_normalize, pdf_extract, pdf_chunk) now accept the verbose parameter and handle the structured responses appropriately.
6. Comprehensive test coverage - Added parametrized tests for both verbose modes across all blob functions.

Fixes #<403365429> 🦕

[sycai]

we usually don't put logics in unit tests: go/unit-testing-practices?polyglot=python#logic

In this case, we should use two test methods to avoid the "if-else" branch: test_blob_exif and text_blob_exif_verbose

The same suggestion applies to other test methods too.

[shuoweil]

I have modified all testcases as suggested. I also checked the failed testcase. They are unrelated to this change.