Add getDimensionsClassesAndStyles function and related tests

[Swoyamjeetcodes]

What?

Closes #74518

This PR introduces a new experimental helper for Dimensions block support serialization:
__experimentalGetDimensionsClassesAndStyles.

The helper returns { className, style } for dimensions-related block supports when their serialization is intentionally skipped.

Why?

Gutenberg currently provides helper utilities for several block supports (color, spacing, border, shadow, typography) to generate CSS classes and inline styles when serialization is skipped. However, there was no equivalent helper for Dimensions block support (e.g. width, height, min-height, aspect ratio).

As a result, block authors had to reimplement internal logic to correctly apply dimensions styles to inner elements, leading to duplication and inconsistencies across blocks.

This PR fills that gap by providing a dedicated helper that aligns Dimensions with the rest of the Block API.

How?

• Added a new helper function getDimensionsClassesAndStyles that derives dimensions-related class names and inline styles from style.dimensions.
• Exposed the helper as __experimentalGetDimensionsClassesAndStyles via @wordpress/block-editor.
• Implemented conflict resolution logic between aspectRatio and height-related properties to mirror existing internal behavior.
• Added unit tests covering aspect ratio, width, height, minHeight, and conflict resolution scenarios.

Testing Instructions

1. Run the block-editor unit tests:

   npm run test:unit packages/block-editor

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Co-authored-by: Swoyamjeetcodes <[email protected]>
Co-authored-by: mrleemon <[email protected]>

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