esp_jpeg: Add support for default Huffman tables

[tore-espressif]

Summary:
This PR introduces an enhancement to the JPEG decoder in the ESP-IDF library to enable decoding of JPEG images that do not include Huffman tables. Specifically, this update enables decoding of non-standard JPEG frames, such as those produced by certain USB cameras (e.g., Logitech C270), which omit Huffman tables to save space and instead rely on predefined quantization and color subsampling settings. This PR adds robustness to the JPEG decoder by expanding support for such non-standard formats.
Key Changes

• JPEG Decoder Update:
  Modified the JPEG decoder to support images without Huffman tables, allowing the library to apply default Huffman tables when none are found in the input data.
  This change is essential for handling image data from specific USB cameras that omit Huffman tables.

• Double Block Size Support (16x8):
  Added handling for double-block size in images (16x8 pixels), a structure unique to frames from certain USB cameras, which diverge from the more common 8x8 block size.
  Improved parsing logic to ensure accurate decompression for such formats while maintaining compatibility with standard JPEG images.

• Test Case Addition:
  Created a new test case for JPEG decompression without Huffman tables to validate decoding accuracy and RGB888 output correctness.
  The test compares decompressed image data to reference RGB888 arrays, allowing a color tolerance of ±16 for minor discrepancies, as certain decoding processes (e.g., Windows-based decoders) might use slight variations in default tables.
  The test validates the decompressed image dimensions and color data to ensure it falls within acceptable margins of error.

Testing and Validation

• New Test Coverage: The newly added test case simulates the decoding of a JPEG file without Huffman tables and checks output against expected RGB888 data, allowing for a minor margin of color error.
• Backward Compatibility: No impact on decoding standard JPEG images, as the decoder falls back on default tables only when Huffman tables are absent in the input.

Motivation and Context

Some USB cameras, such as the Logitech C270, output JPEG frames without Huffman tables, which standard JPEG decoders often cannot process. By introducing support for these cases, this PR enables ESP-IDF to handle a broader range of JPEG image formats, improving its utility in applications that interface with USB cameras or other devices producing such non-standard JPEG frames.

[tore-espressif]

@suda-morris @igrr PTAL or please help me find someone for review, thank you

FYI @espzav

[github-actions]

Test Results

15 files  15 suites   1m 19s ⏱️
 2 tests  2 ✅ 0 💤 0 ❌
10 runs  10 ✅ 0 💤 0 ❌

Results for commit e793c31.

♻️ This comment has been updated with latest results.

[igrr]

Overall LGTM, left a few minor comments.

[tore-espressif]

Thank you for the review @igrr ! I implemented your comments and also tested on esp-idf examples that use esp_jpeg

[tore-espressif]

Thank you for the review @igrr ! I implemented your comments and also tested on esp-idf examples that use esp_jpeg

@igrr Also tested with USB camera. Please let me know if you want to have a second look or I can merge, thanks!