[Reusable blocks] Edit single instance at a time, cancel on escape key

[adamziel]

Description

This PR reinstates the changes from #21427 that were reverted after making reusable blocks a separate package:

• Editing reusable blocks only affects the edited instance until the changes are saved. This means that other instances of the same reusable blocks will remain unaffected during editing.
• Escape key cancels the editing.

How has this been tested?

Go to post editor and confirm the two changes described above indeed work.

Types of changes

Bug fix

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.

[github-actions]

Size Change: +90 B (0%)

Total Size: 1.2 MB

Filename	Size	Change
build/block-library/index.js	148 kB	+90 B (0%)

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.14 kB	0 B
build/annotations/index.js	3.8 kB	0 B
build/api-fetch/index.js	3.42 kB	0 B
build/autop/index.js	2.84 kB	0 B
build/blob/index.js	664 B	0 B
build/block-directory/index.js	8.72 kB	0 B
build/block-directory/style-rtl.css	943 B	0 B
build/block-directory/style.css	942 B	0 B
build/block-editor/index.js	134 kB	0 B
build/block-editor/style-rtl.css	11.3 kB	0 B
build/block-editor/style.css	11.3 kB	0 B
build/block-library/editor-rtl.css	8.95 kB	0 B
build/block-library/editor.css	8.95 kB	0 B
build/block-library/style-rtl.css	8.27 kB	0 B
build/block-library/style.css	8.27 kB	0 B
build/block-library/theme-rtl.css	789 B	0 B
build/block-library/theme.css	790 B	0 B
build/block-serialization-default-parser/index.js	1.87 kB	0 B
build/block-serialization-spec-parser/index.js	3.06 kB	0 B
build/blocks/index.js	48.1 kB	0 B
build/components/index.js	172 kB	0 B
build/components/style-rtl.css	15.3 kB	0 B
build/components/style.css	15.3 kB	0 B
build/compose/index.js	9.95 kB	0 B
build/core-data/index.js	14.8 kB	0 B
build/data-controls/index.js	828 B	0 B
build/data/index.js	8.8 kB	0 B
build/date/index.js	11.2 kB	0 B
build/deprecated/index.js	768 B	0 B
build/dom-ready/index.js	571 B	0 B
build/dom/index.js	4.95 kB	0 B
build/edit-navigation/index.js	11.1 kB	0 B
build/edit-navigation/style-rtl.css	881 B	0 B
build/edit-navigation/style.css	885 B	0 B
build/edit-post/index.js	306 kB	0 B
build/edit-post/style-rtl.css	6.42 kB	0 B
build/edit-post/style.css	6.4 kB	0 B
build/edit-site/index.js	24 kB	0 B
build/edit-site/style-rtl.css	3.92 kB	0 B
build/edit-site/style.css	3.92 kB	0 B
build/edit-widgets/index.js	26.3 kB	0 B
build/edit-widgets/style-rtl.css	3.13 kB	0 B
build/edit-widgets/style.css	3.13 kB	0 B
build/editor/editor-styles-rtl.css	476 B	0 B
build/editor/editor-styles.css	478 B	0 B
build/editor/index.js	43.3 kB	0 B
build/editor/style-rtl.css	3.85 kB	0 B
build/editor/style.css	3.85 kB	0 B
build/element/index.js	4.62 kB	0 B
build/escape-html/index.js	735 B	0 B
build/format-library/index.js	6.87 kB	0 B
build/format-library/style-rtl.css	547 B	0 B
build/format-library/style.css	548 B	0 B
build/hooks/index.js	2.27 kB	0 B
build/html-entities/index.js	623 B	0 B
build/i18n/index.js	3.57 kB	0 B
build/is-shallow-equal/index.js	698 B	0 B
build/keyboard-shortcuts/index.js	2.54 kB	0 B
build/keycodes/index.js	1.94 kB	0 B
build/list-reusable-blocks/index.js	3.1 kB	0 B
build/list-reusable-blocks/style-rtl.css	476 B	0 B
build/list-reusable-blocks/style.css	476 B	0 B
build/media-utils/index.js	5.32 kB	0 B
build/notices/index.js	1.81 kB	0 B
build/nux/index.js	3.42 kB	0 B
build/nux/style-rtl.css	671 B	0 B
build/nux/style.css	668 B	0 B
build/plugins/index.js	2.56 kB	0 B
build/primitives/index.js	1.43 kB	0 B
build/priority-queue/index.js	790 B	0 B
build/redux-routine/index.js	2.84 kB	0 B
build/reusable-blocks/index.js	2.92 kB	0 B
build/rich-text/index.js	13.3 kB	0 B
build/server-side-render/index.js	2.77 kB	0 B
build/shortcode/index.js	1.69 kB	0 B
build/token-list/index.js	1.27 kB	0 B
build/url/index.js	4.06 kB	0 B
build/viewport/index.js	1.86 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.22 kB	0 B

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[ZebulanStanphill]

Tests appear to be failing because creating a new reusable block doesn't work properly. When you click "Add to Reusable blocks", the content appears to be erased (though if you stop editing the new reusable block, it will reappear.

The problem is that the local state for a brand new reusable block isn't set properly. I guess it has something to do with how a newly-created reusable block is immediately put into edit mode.

Everything else seems to be working correctly in this PR. Thanks for working on this. 👍

[adamziel]

@ZebulanStanphill @paaljoachim I was about to rebase and fix the bugs, but it looks like this PR is obsolete now that reusable blocks are saved in the same way as template parts? I'm closing it, but feel free to reopen and comment if I'm wrong – I'm happy to get it across the line.