Paragraph with Image: Transform to image

[dhananjaykuber]

Fixes #56344

What?

This PR adds the ability to transform a paragraph block containing only an inline image into a proper image block, preserving all image attributes and alignment settings.

Why?

Users sometimes end up with inline images inside paragraph blocks with no straightforward way to convert them into proper image blocks. This creates a suboptimal editing experience, especially when users want to take advantage of image block-specific features.

How?

Added a new block transform to the paragraph block that:

1. Detects when a paragraph contains exactly one inline image with no other content
2. Preserves all image attributes (src, alt, title, dimensions, class)
3. Maintains existing alignment settings
4. Handles linked images by preserving link destination and URL
5. Shows the transform option in the block toolbar when appropriate

Testing Instructions

1. Open the block editor
2. Create a new paragraph block
3. Insert an inline image into the paragraph
4. Delete any text in the paragraph so only the image remains
5. Click the block toolbar's transform button (three dots)
6. Verify that "Transform to Image block" appears as an option
7. Click the transform option and verify that:
   The image appears correctly in its new block
   a. All image attributes are preserved
   b. Alignment settings remain intact
   c. If the image was linked, the link is maintained

Screenshots or screencast

screen-capture.1.webm

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Co-authored-by: dhananjaykuber <dhananjaykuber@git.wordpress.org>
Co-authored-by: carolinan <poena@git.wordpress.org>
Co-authored-by: scruffian <scruffian@git.wordpress.org>

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