Add getPixelDataFromMedia function for image color detection

[Adityacode-hub]

This PR adds a new function to extract pixel data from media elements, enabling color detection functionality for uploaded images and webcam feeds.

Changes Made

• Added getPixelDataFromMedia() function to SensorsBlocks.js
• Function extracts RGBA pixel data from media elements (images/video)
• Added comprehensive documentation explaining the function's purpose and current limitations
• Documentation clarifies that getPixelData() currently only works with turtle-drawn content on overlayCanvas

Purpose

This function is part of my preparation for the GSoC "Color sensor for Music Blocks" project. The goal is to extend color detection capabilities beyond turtle graphics to work with:

• Uploaded images
• Webcam feed
• Other media sources

Technical Details

The function uses canvas context to draw and extract pixel data from media elements, making it compatible with various image sources.

Testing

• Function successfully extracts pixel data from image elements
• Tested locally with different image types

Context

This is part of splitting PR #4784 into smaller, focused pull requests as requested by @walterbender for easier review.

Related Commits

• 6ed50ba: Add getPixelDataFromMedia function for image color detection
• e6129d5: Add documentation comment to getPixelData function

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.