Block editor: Remove stale reusable block z-index styles (#77774)

* Block editor: Inline reusable block z-index

* Remove stale class

* Add changelog

Co-authored-by: mirka <0mirka00@git.wordpress.org>
Co-authored-by: ramonjd <ramonopoly@git.wordpress.org>

Author: mirka

packages/base-styles/CHANGELOG.md

@@ -4,11 +4,12 @@
 
 ### Breaking Changes
 
--   Remove the following entries from the `z-index()` helper ([#77619](https://github.com/WordPress/gutenberg/pull/77619), [#77620](https://github.com/WordPress/gutenberg/pull/77620), [#77621](https://github.com/WordPress/gutenberg/pull/77621), [#77714](https://github.com/WordPress/gutenberg/pull/77714), [#77715](https://github.com/WordPress/gutenberg/pull/77715), [#77717](https://github.com/WordPress/gutenberg/pull/77717)):
+-   Remove the following entries from the `z-index()` helper ([#77619](https://github.com/WordPress/gutenberg/pull/77619), [#77620](https://github.com/WordPress/gutenberg/pull/77620), [#77621](https://github.com/WordPress/gutenberg/pull/77621), [#77714](https://github.com/WordPress/gutenberg/pull/77714), [#77715](https://github.com/WordPress/gutenberg/pull/77715), [#77717](https://github.com/WordPress/gutenberg/pull/77717), [#77774](https://github.com/WordPress/gutenberg/pull/77774)):
     -   `.block-editor-block-contextual-toolbar`
     -   `.block-editor-block-list__block {core/image aligned wide or fullwide}`
     -   `.block-editor-block-list__block::before`
     -   `.block-editor-block-list__block.has-block-overlay`
+    -   `.block-editor-block-list__block .reusable-block-edit-panel *`
     -   `.block-editor-block-list__insertion-point`
     -   `.block-editor-block-switcher__arrow`
     -   `.block-editor-url-input__suggestions`

packages/base-styles/_z-index.scss

@@ -38,8 +38,6 @@ $z-layers: (
 	// The draggable element should show up above the entire UI
 	".components-draggable__clone": 1000000000,
 
-	".block-editor-block-list__block .reusable-block-edit-panel *": 1,
-
 	// Show drop zone above most standard content, but below any overlays
 	".components-drop-zone": 40,
 	".components-drop-zone__content": 50,

packages/block-editor/src/components/block-list/content.scss

@@ -153,10 +153,6 @@ _::-webkit-full-page-media, _:future, :root [data-has-multi-selection="true"] .b
 		}
 	}
 
-	.reusable-block-edit-panel * {
-		z-index: z-index(".block-editor-block-list__block .reusable-block-edit-panel *");
-	}
-
 	/**
 	 * Notices
 	 */