Reinitialize the iframe after the parent block is moved around

[adamziel]

Description

As reported in #6146, YouTube block becomes blank when the block is moved down (reordered). The root cause of this issue is the fact that browsers tend to reload the iframe if it's moved around in the DOM Tree, and the fact that React does not correctly dispatch the onLoad event in that case (see facebook/react#18752).

This PR changes the way we register the iframe sandbox initialization callback from onLoad= to iframe.addEventListener. This skips the React event dispatching machinery and keeps the code running.

Before:

After:

Fixes #6146

How has this been tested?

Tested locally

Types of changes

Non-breaking changes

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: -705 B (0%)

Total Size: 816 kB

Filename	Size	Change
build/block-directory/index.js	6.23 kB	-1 B
build/block-editor/index.js	106 kB	+128 B (0%)
build/block-editor/style-rtl.css	10.2 kB	+2 B (0%)
build/block-editor/style.css	10.2 kB	+2 B (0%)
build/block-library/editor-rtl.css	7.03 kB	-26 B (0%)
build/block-library/editor.css	7.03 kB	-26 B (0%)
build/block-library/index.js	114 kB	+1.28 kB (1%)
build/blocks/index.js	48.1 kB	-1 B
build/components/index.js	179 kB	+43 B (0%)
build/components/style-rtl.css	16.9 kB	-8 B (0%)
build/components/style.css	16.9 kB	-8 B (0%)
build/compose/index.js	6.66 kB	+2 B (0%)
build/data/index.js	8.44 kB	+13 B (0%)
build/edit-post/index.js	27.6 kB	-188 B (0%)
build/edit-post/style-rtl.css	12.2 kB	-121 B (0%)
build/edit-post/style.css	12.2 kB	-122 B (1%)
build/edit-site/index.js	10.9 kB	-126 B (1%)
build/edit-site/style-rtl.css	5.11 kB	-151 B (2%)
build/edit-site/style.css	5.11 kB	-147 B (2%)
build/edit-widgets/index.js	7.5 kB	-831 B (11%)	👏
build/edit-widgets/style-rtl.css	4.67 kB	-336 B (7%)	✅
build/edit-widgets/style.css	4.66 kB	-338 B (7%)	✅
build/editor/index.js	43.6 kB	+244 B (0%)
build/keyboard-shortcuts/index.js	2.51 kB	-2 B (0%)
build/list-reusable-blocks/index.js	3.12 kB	+1 B
build/media-utils/index.js	5.29 kB	+1 B
build/plugins/index.js	2.67 kB	-1 B
build/redux-routine/index.js	2.85 kB	+9 B (0%)
build/rich-text/index.js	14.8 kB	+1 B

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.02 kB	0 B
build/annotations/index.js	3.62 kB	0 B
build/api-fetch/index.js	4.08 kB	0 B
build/autop/index.js	2.82 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/style-rtl.css	760 B	0 B
build/block-directory/style.css	761 B	0 B
build/block-library/style-rtl.css	7.14 kB	0 B
build/block-library/style.css	7.14 kB	0 B
build/block-library/theme-rtl.css	683 B	0 B
build/block-library/theme.css	685 B	0 B
build/block-serialization-default-parser/index.js	1.88 kB	0 B
build/block-serialization-spec-parser/index.js	3.1 kB	0 B
build/core-data/index.js	11.4 kB	0 B
build/data-controls/index.js	1.29 kB	0 B
build/date/index.js	5.47 kB	0 B
build/deprecated/index.js	772 B	0 B
build/dom-ready/index.js	568 B	0 B
build/dom/index.js	3.1 kB	0 B
build/edit-navigation/index.js	3.54 kB	0 B
build/edit-navigation/style-rtl.css	485 B	0 B
build/edit-navigation/style.css	485 B	0 B
build/editor/editor-styles-rtl.css	428 B	0 B
build/editor/editor-styles.css	431 B	0 B
build/editor/style-rtl.css	3.27 kB	0 B
build/editor/style.css	3.27 kB	0 B
build/element/index.js	4.65 kB	0 B
build/escape-html/index.js	733 B	0 B
build/format-library/index.js	7.63 kB	0 B
build/format-library/style-rtl.css	502 B	0 B
build/format-library/style.css	502 B	0 B
build/hooks/index.js	2.13 kB	0 B
build/html-entities/index.js	622 B	0 B
build/i18n/index.js	3.56 kB	0 B
build/is-shallow-equal/index.js	710 B	0 B
build/keycodes/index.js	1.94 kB	0 B
build/list-reusable-blocks/style-rtl.css	226 B	0 B
build/list-reusable-blocks/style.css	226 B	0 B
build/notices/index.js	1.79 kB	0 B
build/nux/index.js	3.4 kB	0 B
build/nux/style-rtl.css	616 B	0 B
build/nux/style.css	613 B	0 B
build/primitives/index.js	1.5 kB	0 B
build/priority-queue/index.js	789 B	0 B
build/server-side-render/index.js	2.68 kB	0 B
build/shortcode/index.js	1.7 kB	0 B
build/token-list/index.js	1.28 kB	0 B
build/url/index.js	4.02 kB	0 B
build/viewport/index.js	1.84 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.18 kB	0 B

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[draganescu]

Code looks good and problem is fixed