Editor: Render post preview action as a menu item

[ciampo]

Follow-up to #80093.

What?

Renders “Preview in new tab” with the shared MenuItem pattern in the View dropdown.

Why?

The action used a custom Button, so its typography and icon layout could differ from sibling menu items.

How?

Adds a menu-item presentation that shares the existing preview state and save flow. When enabled, the action still renders as an anchor with its preview URL and named target; the click is intercepted only to open or reuse the tab before the asynchronous preview save finishes.

Removes the custom layout styles that are no longer needed.

Testing Instructions

Open a post, open the View dropdown, and confirm “Preview in new tab” matches the typography and layout of the other menu items. Activate “Preview in new tab” and confirm the preview opens in a new tab.

1. Run npm run test:unit packages/editor/src/components/post-preview-button/test -- --runInBand.
2. Run npm run lint:js -- packages/editor/src/components/post-preview-button/index.js packages/editor/src/components/post-preview-button/test/index.js packages/editor/src/components/preview-dropdown/index.js.
3. Run npm run lint:css -- packages/editor/src/components/preview-dropdown/style.scss.
4. Run npm run build.

Testing Instructions for Keyboard

1. Focus the View button and press Enter or Space.
2. Use the arrow keys to reach “Preview in new tab”.
3. Press Enter and confirm the menu closes and the preview opens in a new tab.
4. Reopen the menu and press Escape to confirm focus returns to the View button.

Screenshots or screencast

Before	After

Use of AI Tools

Implemented and verified with assistance from OpenAI Codex.

[github-actions]

Size Change: -3.44 kB (-0.04%)

Total Size: 7.71 MB

📦 View Changed

Filename	Size	Change
build/modules/block-library/playlist/view.min.js	15.8 kB	-961 B (-5.72%)	✅
build/scripts/block-library/index.min.js	348 kB	-1.91 kB (-0.55%)
build/scripts/editor/index.min.js	495 kB	+1 B (0%)
build/styles/block-library/editor-rtl.css	12.7 kB	-25 B (-0.2%)
build/styles/block-library/editor-rtl.min.css	10.4 kB	-23 B (-0.22%)
build/styles/block-library/editor.css	12.8 kB	-24 B (-0.19%)
build/styles/block-library/editor.min.css	10.4 kB	-21 B (-0.2%)
build/styles/block-library/playlist/editor-rtl.css	120 B	-55 B (-31.43%)	🎉
build/styles/block-library/playlist/editor-rtl.min.css	112 B	-45 B (-28.66%)	🎉
build/styles/block-library/playlist/editor.css	120 B	-55 B (-31.43%)	🎉
build/styles/block-library/playlist/editor.min.css	112 B	-45 B (-28.66%)	🎉
build/styles/block-library/playlist/style-rtl.css	2.12 kB	-24 B (-1.12%)
build/styles/block-library/playlist/style-rtl.min.css	2.02 kB	-23 B (-1.12%)
build/styles/block-library/playlist/style.css	2.12 kB	-23 B (-1.07%)
build/styles/block-library/playlist/style.min.css	2.03 kB	-22 B (-1.07%)
build/styles/block-library/style-rtl.css	22.3 kB	-24 B (-0.11%)
build/styles/block-library/style-rtl.min.css	18.8 kB	-33 B (-0.18%)
build/styles/block-library/style.css	22.4 kB	-20 B (-0.09%)
build/styles/block-library/style.min.css	18.7 kB	-36 B (-0.19%)
build/styles/editor/style-rtl.css	30.9 kB	-16 B (-0.05%)
build/styles/editor/style-rtl.min.css	26.2 kB	-14 B (-0.05%)
build/styles/editor/style.css	30.9 kB	-19 B (-0.06%)
build/styles/editor/style.min.css	26.2 kB	-16 B (-0.06%)

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[github-actions]

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Co-authored-by: ciampo <mciampini@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>

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[t-hamano]

LGTM!