Add unlink URL in buttons block

[ntsekouras]

Description

Resolves #23205

When we are adding a Button in Buttons component we are letting the user to add a link to it. If they do though, then they only have the option to change it and not even set it empty, due to URL input validation.

This PR gives the option to users to remove the link and just have a Button without pointing to a URL.

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: +81 B (0%)

Total Size: 1.13 MB

Filename	Size	Change
build/autop/index.js	2.82 kB	-1 B
build/block-directory/index.js	7.37 kB	-1 B
build/block-editor/index.js	109 kB	-2 B (0%)
build/block-library/index.js	130 kB	+184 B (0%)
build/blocks/index.js	48.2 kB	+2 B (0%)
build/components/index.js	197 kB	-91 B (0%)
build/compose/index.js	9.62 kB	-1 B
build/data/index.js	8.44 kB	-1 B
build/edit-post/index.js	303 kB	-3 B (0%)
build/edit-site/index.js	16.6 kB	+1 B
build/edit-widgets/index.js	9.32 kB	-1 B
build/editor/index.js	44.9 kB	-2 B (0%)
build/keyboard-shortcuts/index.js	2.51 kB	+1 B
build/list-reusable-blocks/index.js	3.13 kB	-1 B
build/plugins/index.js	2.56 kB	-1 B
build/rich-text/index.js	14 kB	-2 B (0%)

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.14 kB	0 B
build/annotations/index.js	3.62 kB	0 B
build/api-fetch/index.js	3.4 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/style-rtl.css	941 B	0 B
build/block-directory/style.css	942 B	0 B
build/block-editor/style-rtl.css	10.9 kB	0 B
build/block-editor/style.css	10.9 kB	0 B
build/block-library/editor-rtl.css	7.59 kB	0 B
build/block-library/editor.css	7.6 kB	0 B
build/block-library/style-rtl.css	8.04 kB	0 B
build/block-library/style.css	8.04 kB	0 B
build/block-library/theme-rtl.css	730 B	0 B
build/block-library/theme.css	732 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	15.8 kB	0 B
build/components/style.css	15.8 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	569 B	0 B
build/dom/index.js	3.19 kB	0 B
build/edit-navigation/index.js	9.87 kB	0 B
build/edit-navigation/style-rtl.css	1.02 kB	0 B
build/edit-navigation/style.css	1.02 kB	0 B
build/edit-post/style-rtl.css	5.5 kB	0 B
build/edit-post/style.css	5.5 kB	0 B
build/edit-site/style-rtl.css	3.02 kB	0 B
build/edit-site/style.css	3.02 kB	0 B
build/edit-widgets/style-rtl.css	2.42 kB	0 B
build/edit-widgets/style.css	2.42 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	3.81 kB	0 B
build/editor/style.css	3.81 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	7.73 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	2.13 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	450 B	0 B
build/list-reusable-blocks/style.css	451 B	0 B
build/media-utils/index.js	5.29 kB	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	663 B	0 B
build/nux/style.css	660 B	0 B
build/primitives/index.js	1.5 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	2.68 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	4.06 kB	0 B
build/viewport/index.js	1.85 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.17 kB	0 B

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[ellatrix]

Feels good to me. Perhaps good to have an extra design check.

[ellatrix]

@jasmussen @MichaelArestad I think Tammie worked on this?

[jasmussen]

What I see in this branch:

What I see in master:

Yep. This is a nice improvement.

The positioning of the URL popover feels totally arbitrary, but that's not a fault of this PR, and something worth fixing separately. Nice.