Fix Global Styles sidebar block selection on zoom out mode (#50708)

* Fix Global Styles sidebar block selection on zoom out mode

* [Global Styles]: Enable deep linking to the selected block only in the `Blocks` screen

packages/edit-site/src/components/global-styles/ui.js

@@ -18,7 +18,7 @@ import { __, sprintf, _n } from '@wordpress/i18n';
 import { store as preferencesStore } from '@wordpress/preferences';
 import { moreVertical } from '@wordpress/icons';
 import { store as coreStore } from '@wordpress/core-data';
-import { useEffect, useRef } from '@wordpress/element';
+import { useEffect } from '@wordpress/element';
 
 /**
  * Internal dependencies
@@ -203,7 +203,6 @@ function GlobalStylesStyleBook() {
 
 function GlobalStylesBlockLink() {
 	const navigator = useNavigator();
-	const isMounted = useRef();
 	const { selectedBlockName, selectedBlockClientId } = useSelect(
 		( select ) => {
 			const { getSelectedBlockClientId, getBlockName } =
@@ -217,20 +216,23 @@ function GlobalStylesBlockLink() {
 		[]
 	);
 	const blockHasGlobalStyles = useBlockHasGlobalStyles( selectedBlockName );
+	// When we're in the `Blocks` screen enable deep linking to the selected block.
 	useEffect( () => {
-		// Avoid navigating to the block screen on mount.
-		if ( ! isMounted.current ) {
-			isMounted.current = true;
+		if ( ! selectedBlockClientId || ! blockHasGlobalStyles ) {
 			return;
 		}
-		if ( ! selectedBlockClientId || ! blockHasGlobalStyles ) {
+		const currentPath = navigator.location.path;
+		if (
+			currentPath !== '/blocks' &&
+			! currentPath.startsWith( '/blocks/' )
+		) {
 			return;
 		}
-		const path = '/blocks/' + encodeURIComponent( selectedBlockName );
+		const newPath = '/blocks/' + encodeURIComponent( selectedBlockName );
 		// Avoid navigating to the same path. This can happen when selecting
 		// a new block of the same type.
-		if ( path !== navigator.location.path ) {
-			navigator.goTo( path, { skipFocus: true } );
+		if ( newPath !== currentPath ) {
+			navigator.goTo( newPath, { skipFocus: true } );
 		}
 	}, [ selectedBlockClientId, selectedBlockName, blockHasGlobalStyles ] );
 }