Fix block merging regression

[youknowriad]

closes #23808 regressed in #23394

Fixes merging two textual blocks together. The keyboard shortcut for multi blocks removal was being triggered.

• Add an end2end test.

Testing instructions

• Make sure merging paragraphs work
• Make sure removing an image block if it's selected works (backspace)
• Make sure backspaces removes multi-selection.

[github-actions]

Size Change: +91 B (0%)

Total Size: 1.14 MB

Filename	Size	Change
build/block-editor/index.js	115 kB	+75 B (0%)
build/block-library/index.js	132 kB	+1 B
build/blocks/index.js	48.2 kB	-2 B (0%)
build/components/index.js	199 kB	+16 B (0%)
build/edit-post/index.js	304 kB	+1 B
build/edit-site/index.js	16.6 kB	-1 B
build/edit-widgets/index.js	9.35 kB	-2 B (0%)
build/editor/index.js	45.1 kB	+1 B
build/format-library/index.js	7.72 kB	+3 B (0%)
build/keyboard-shortcuts/index.js	2.51 kB	+1 B
build/media-utils/index.js	5.32 kB	-1 B
build/rich-text/index.js	13.9 kB	-1 B

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.14 kB	0 B
build/annotations/index.js	3.67 kB	0 B
build/api-fetch/index.js	3.39 kB	0 B
build/autop/index.js	2.82 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/index.js	7.67 kB	0 B
build/block-directory/style-rtl.css	944 B	0 B
build/block-directory/style.css	945 B	0 B
build/block-editor/style-rtl.css	10.8 kB	0 B
build/block-editor/style.css	10.8 kB	0 B
build/block-library/editor-rtl.css	7.6 kB	0 B
build/block-library/editor.css	7.59 kB	0 B
build/block-library/style-rtl.css	7.77 kB	0 B
build/block-library/style.css	7.77 kB	0 B
build/block-library/theme-rtl.css	728 B	0 B
build/block-library/theme.css	729 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/components/style-rtl.css	15.9 kB	0 B
build/components/style.css	15.8 kB	0 B
build/compose/index.js	9.67 kB	0 B
build/core-data/index.js	11.4 kB	0 B
build/data-controls/index.js	1.29 kB	0 B
build/data/index.js	8.46 kB	0 B
build/date/index.js	5.38 kB	0 B
build/deprecated/index.js	772 B	0 B
build/dom-ready/index.js	569 B	0 B
build/dom/index.js	3.23 kB	0 B
build/edit-navigation/index.js	10.8 kB	0 B
build/edit-navigation/style-rtl.css	1.08 kB	0 B
build/edit-navigation/style.css	1.08 kB	0 B
build/edit-post/style-rtl.css	5.59 kB	0 B
build/edit-post/style.css	5.58 kB	0 B
build/edit-site/style-rtl.css	3.03 kB	0 B
build/edit-site/style.css	3.03 kB	0 B
build/edit-widgets/style-rtl.css	2.45 kB	0 B
build/edit-widgets/style.css	2.45 kB	0 B
build/editor/editor-styles-rtl.css	537 B	0 B
build/editor/editor-styles.css	539 B	0 B
build/editor/style-rtl.css	3.78 kB	0 B
build/editor/style.css	3.78 kB	0 B
build/element/index.js	4.65 kB	0 B
build/escape-html/index.js	733 B	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	2.13 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	709 B	0 B
build/keycodes/index.js	1.94 kB	0 B
build/list-reusable-blocks/index.js	3.12 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/notices/index.js	1.79 kB	0 B
build/nux/index.js	3.4 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	1.4 kB	0 B
build/priority-queue/index.js	789 B	0 B
build/redux-routine/index.js	2.85 kB	0 B
build/server-side-render/index.js	2.71 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	4.06 kB	0 B
build/viewport/index.js	1.85 kB	0 B
build/warning/index.js	1.13 kB	0 B
build/wordcount/index.js	1.17 kB	0 B

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[ellatrix]

We didn't already have an e2e test for this? 🤔

[youknowriad]

I also thought we had but apparently no 🤷 We had one for "forward merge".