RichText: make window/document agnostic

[ellatrix]

Description

I'm splitting this out from #21102. This PR will be needed to allow rich text to work inside an iframe. To be honest, this is something that should be done anyway, as it's good practice not to depend on globals. This PR uses the rich text element's window/document rather than the global window/document.

How has this been tested?

Screenshots

Types of 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: +978 B (0%)

Total Size: 859 kB

Filename	Size	Change
build/autop/index.js	2.58 kB	+1 B
build/block-editor/index.js	102 kB	+1.06 kB (1%)
build/block-library/index.js	110 kB	-179 B (0%)
build/block-library/style-rtl.css	7.43 kB	+20 B (0%)
build/block-library/style.css	7.44 kB	+20 B (0%)
build/blocks/index.js	57.5 kB	+1 B
build/components/index.js	191 kB	-7 B (0%)
build/compose/index.js	6.21 kB	-2 B (0%)
build/core-data/index.js	10.6 kB	+1 B
build/data/index.js	8.25 kB	-1 B
build/edit-post/index.js	91.2 kB	-1 B
build/edit-site/index.js	6.72 kB	-1 B
build/edit-widgets/index.js	4.43 kB	-4 B (0%)
build/editor/index.js	43.8 kB	+2 B (0%)
build/element/index.js	4.44 kB	+2 B (0%)
build/format-library/index.js	6.95 kB	-6 B (0%)
build/keyboard-shortcuts/index.js	2.3 kB	+1 B
build/list-reusable-blocks/index.js	2.99 kB	+1 B
build/media-utils/index.js	4.84 kB	+1 B
build/nux/index.js	3.01 kB	+1 B
build/rich-text/index.js	14.4 kB	+65 B (0%)
build/server-side-render/index.js	2.55 kB	-1 B

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	998 B	0 B
build/annotations/index.js	3.43 kB	0 B
build/api-fetch/index.js	3.39 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/index.js	6.02 kB	0 B
build/block-directory/style-rtl.css	760 B	0 B
build/block-directory/style.css	760 B	0 B
build/block-editor/style-rtl.css	11 kB	0 B
build/block-editor/style.css	11 kB	0 B
build/block-library/editor-rtl.css	7.24 kB	0 B
build/block-library/editor.css	7.24 kB	0 B
build/block-library/theme-rtl.css	669 B	0 B
build/block-library/theme.css	671 B	0 B
build/block-serialization-default-parser/index.js	1.65 kB	0 B
build/block-serialization-spec-parser/index.js	3.1 kB	0 B
build/components/style-rtl.css	15.8 kB	0 B
build/components/style.css	15.7 kB	0 B
build/data-controls/index.js	1.04 kB	0 B
build/date/index.js	5.37 kB	0 B
build/deprecated/index.js	771 B	0 B
build/dom-ready/index.js	568 B	0 B
build/dom/index.js	3.06 kB	0 B
build/edit-post/style-rtl.css	8.47 kB	0 B
build/edit-post/style.css	8.46 kB	0 B
build/edit-site/style-rtl.css	2.88 kB	0 B
build/edit-site/style.css	2.88 kB	0 B
build/edit-widgets/style-rtl.css	2.58 kB	0 B
build/edit-widgets/style.css	2.58 kB	0 B
build/editor/editor-styles-rtl.css	381 B	0 B
build/editor/editor-styles.css	382 B	0 B
build/editor/style-rtl.css	4 kB	0 B
build/editor/style.css	3.98 kB	0 B
build/escape-html/index.js	733 B	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	1.93 kB	0 B
build/html-entities/index.js	622 B	0 B
build/i18n/index.js	3.49 kB	0 B
build/is-shallow-equal/index.js	710 B	0 B
build/keycodes/index.js	1.69 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	1.57 kB	0 B
build/nux/style-rtl.css	616 B	0 B
build/nux/style.css	613 B	0 B
build/plugins/index.js	2.54 kB	0 B
build/primitives/index.js	1.5 kB	0 B
build/priority-queue/index.js	781 B	0 B
build/redux-routine/index.js	2.84 kB	0 B
build/shortcode/index.js	1.7 kB	0 B
build/token-list/index.js	1.27 kB	0 B
build/url/index.js	4.01 kB	0 B
build/viewport/index.js	1.61 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.18 kB	0 B

_{compressed-size-action}

[ellatrix]

Everything is working as expected here.