Fixed block class name attribute handling

[girishpanchal30]

Closes #2996

Summary

Handled the case when the className attribute of a block is an array instead of a string. This can happen when third-party plugins modify the block attributes.

Checklist before the final review

• Included E2E or unit tests for the changes in this PR.
• Visual elements are not affected by independent changes.
• It is at least compatible with the minimum WordPress version.
• It loads additional script in frontend only if it is required.
• Does not impact the Core Web Vitals.
• In case of deprecation, old blocks are safely migrated.
• It is usable in Widgets and FSE.
• Copy/Paste is working if the attributes are modified.
• PR is following the best practices

[pirate-bot]

Bundle Size Diff

Package	Old Size	New Size	Diff
Animations	178.33 KB	178.33 KB	0 B (0.00%)
Blocks	1.65 MB	1.65 MB	0 B (0.00%)
CSS	7.83 KB	7.83 KB	0 B (0.00%)
Dashboard	172.49 KB	172.49 KB	0 B (0.00%)
Onboarding	68.14 KB	68.14 KB	0 B (0.00%)
Export Import	4.73 KB	4.73 KB	0 B (0.00%)
Pro	439.82 KB	439.82 KB	0 B (0.00%)

[pirate-bot]

Plugin build for b890d1a is ready 🛎️!

• Download Otter – Page Builder Blocks & Extensions for Gutenberg - Production ~ Development
• Download Otter Pro - Production ~ Development
• Download Blocks Animation - Production ~ Development
• Download Blocks CSS - Production ~ Development
• Download Blocks Export Import - Production ~ Development

[pirate-bot]

E2E Tests

Playwright Test Status: See serial and parallel matrix jobs

Performance Results

serverResponse: {"q25":368.65,"q50":378.92,"q75":391.98,"cnt":10}, firstPaint: {"q25":1310.18,"q50":1375.26,"q75":1542.54,"cnt":10}, domContentLoaded: {"q25":3410.43,"q50":3418.81,"q75":3438.58,"cnt":10}, loaded: {"q25":3413.4,"q50":3421.62,"q75":3441.33,"cnt":10}, firstContentfulPaint: {"q25":2217.76,"q50":2575.96,"q75":2589.09,"cnt":10}, firstBlock: {"q25":16125.24,"q50":16325.79,"q75":16375.72,"cnt":10}, type: {"q25":24.54,"q50":27.69,"q75":31.92,"cnt":10}, typeWithoutInspector: {"q25":24.58,"q50":26.32,"q75":29.35,"cnt":10}, typeWithTopToolbar: {"q25":30.18,"q50":35.71,"q75":38.18,"cnt":10}, typeContainer: {"q25":14.46,"q50":15.52,"q75":17.18,"cnt":10}, focus: {"q25":123.09,"q50":125.52,"q75":134.45,"cnt":10}, inserterOpen: {"q25":39.86,"q50":43.65,"q75":45.1,"cnt":10}, inserterSearch: {"q25":27.44,"q50":28.78,"q75":30.3,"cnt":10}, inserterHover: {"q25":4.59,"q50":5.18,"q75":5.55,"cnt":20}, loadPatterns: {"q25":1678.86,"q50":1710.75,"q75":1799.02,"cnt":10}, listViewOpen: {"q25":215.62,"q50":227.51,"q75":228.37,"cnt":10}

[Copilot]

Pull request overview

Adds safe normalization for array-valued block class names, preventing frontend rendering and asset-loading errors.

Changes:

• Introduces shared class-name normalization.
• Updates sticky, Font Awesome, animation, Posts Grid, and modal consumers.
• Adds regression tests and updates the standalone CSS sandbox.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
inc/class-registration.php	Adds normalization and updates asset detection.
inc/class-base-css.php	Normalizes animation classes.
inc/render/class-posts-grid-block.php	Safely detects tiled layouts.
inc/css/blocks/class-posts-css.php	Safely evaluates tiled-style CSS.
plugins/otter-pro/inc/render/class-modal-block.php	Normalizes modal wrapper classes.
tests/test-block-class-name.php	Adds regression coverage.
tests/php/foreign-sabberworm-sandbox.php	Loads the new dependency.

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