[Widgets] Auto expand the last selected widget area when opening the inserter

[kevin940726]

Description

Fix #25648 and fix #25650.

Auto expand the last selected widget area when opening the inserter.

Done it by registering a @wordpress/data state widgetAreasOpenState in edit-widgets store. Potentially makes it easier to manage the open state in the future.

This PR fixes two issues together since they are very similar and might be easier to understand when reviewing as a whole.

How has this been tested?

1. Open the widgets screen.
2. The first widget area should default to open.
3. The inserter should insert a block at the top of the first widget area.
4. Close the first widget area, open the second widget area.
5. The inserter should insert a block at the top of the second widget area.
6. Close the second widget area, but without losing its focus.
7. The inserter should expand the second widget area and insert a block at the top of the second widget area.
8. Close all widget areas, click elsewhere to lose their focuses.
9. The inserter should expand the first widget area and insert a block at the top of the first widget area.

Screenshots

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: +249 B (0%)

Total Size: 1.17 MB

Filename	Size	Change
build/block-library/index.js	135 kB	+32 B (0%)
build/edit-widgets/index.js	18.1 kB	+217 B (1%)

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.14 kB	0 B
build/annotations/index.js	3.52 kB	0 B
build/api-fetch/index.js	3.35 kB	0 B
build/autop/index.js	2.72 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/index.js	8.53 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	128 kB	0 B
build/block-editor/style-rtl.css	11.1 kB	0 B
build/block-editor/style.css	11.1 kB	0 B
build/block-library/editor-rtl.css	8.57 kB	0 B
build/block-library/editor.css	8.58 kB	0 B
build/block-library/style-rtl.css	7.61 kB	0 B
build/block-library/style.css	7.6 kB	0 B
build/block-library/theme-rtl.css	741 B	0 B
build/block-library/theme.css	741 B	0 B
build/block-serialization-default-parser/index.js	1.78 kB	0 B
build/block-serialization-spec-parser/index.js	3.1 kB	0 B
build/blocks/index.js	47.5 kB	0 B
build/components/index.js	167 kB	0 B
build/components/style-rtl.css	15.5 kB	0 B
build/components/style.css	15.5 kB	0 B
build/compose/index.js	9.42 kB	0 B
build/core-data/index.js	12 kB	0 B
build/data-controls/index.js	1.27 kB	0 B
build/data/index.js	8.43 kB	0 B
build/date/index.js	31.9 kB	0 B
build/deprecated/index.js	772 B	0 B
build/dom-ready/index.js	568 B	0 B
build/dom/index.js	4.42 kB	0 B
build/edit-navigation/index.js	10.7 kB	0 B
build/edit-navigation/style-rtl.css	868 B	0 B
build/edit-navigation/style.css	871 B	0 B
build/edit-post/index.js	306 kB	0 B
build/edit-post/style-rtl.css	6.25 kB	0 B
build/edit-post/style.css	6.24 kB	0 B
build/edit-site/index.js	20.5 kB	0 B
build/edit-site/style-rtl.css	3.54 kB	0 B
build/edit-site/style.css	3.54 kB	0 B
build/edit-widgets/style-rtl.css	2.82 kB	0 B
build/edit-widgets/style.css	2.82 kB	0 B
build/editor/editor-styles-rtl.css	492 B	0 B
build/editor/editor-styles.css	493 B	0 B
build/editor/index.js	45.4 kB	0 B
build/editor/style-rtl.css	3.83 kB	0 B
build/editor/style.css	3.82 kB	0 B
build/element/index.js	4.44 kB	0 B
build/escape-html/index.js	733 B	0 B
build/format-library/index.js	7.49 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	1.74 kB	0 B
build/html-entities/index.js	621 B	0 B
build/i18n/index.js	3.55 kB	0 B
build/is-shallow-equal/index.js	709 B	0 B
build/keyboard-shortcuts/index.js	2.39 kB	0 B
build/keycodes/index.js	1.85 kB	0 B
build/list-reusable-blocks/index.js	3.02 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	5.12 kB	0 B
build/notices/index.js	1.69 kB	0 B
build/nux/index.js	3.27 kB	0 B
build/nux/style-rtl.css	671 B	0 B
build/nux/style.css	668 B	0 B
build/plugins/index.js	2.44 kB	0 B
build/primitives/index.js	1.34 kB	0 B
build/priority-queue/index.js	789 B	0 B
build/redux-routine/index.js	2.85 kB	0 B
build/rich-text/index.js	13.7 kB	0 B
build/server-side-render/index.js	2.61 kB	0 B
build/shortcode/index.js	1.7 kB	0 B
build/token-list/index.js	1.24 kB	0 B
build/url/index.js	4.06 kB	0 B
build/viewport/index.js	1.74 kB	0 B
build/warning/index.js	1.13 kB	0 B
build/wordcount/index.js	1.17 kB	0 B

_{compressed-size-action}

[adamziel]

The code looks great and the PR works as intended - great job @kevin940726 !