BlockSettingsDropdown: No need to cast 'clientIds' to an array (#59940)

* BlockSettingsDropdown: No need to cast 'clientIds' to an array
* Fix clientId logic for 'onInsertBefore' and 'onInsertAfter' actions

Co-authored-by: Mamaduka <mamaduka@git.wordpress.org>
Co-authored-by: tyxla <tyxla@git.wordpress.org>

packages/block-editor/src/components/block-actions/index.js

@@ -98,16 +98,10 @@ export default function BlockActions( {
 			return removeBlocks( clientIds, updateSelection );
 		},
 		onInsertBefore() {
-			const clientId = Array.isArray( clientIds )
-				? clientIds[ 0 ]
-				: clientId;
-			insertBeforeBlock( clientId );
+			insertBeforeBlock( clientIds[ 0 ] );
 		},
 		onInsertAfter() {
-			const clientId = Array.isArray( clientIds )
-				? clientIds[ clientIds.length - 1 ]
-				: clientId;
-			insertAfterBlock( clientId );
+			insertAfterBlock( clientIds[ clientIds.length - 1 ] );
 		},
 		onMoveTo() {
 			setNavigationMode( true );

packages/block-editor/src/components/block-settings-menu/block-settings-dropdown.js

@@ -46,18 +46,15 @@ function CopyMenuItem( { clientIds, onCopy, label } ) {
 export function BlockSettingsDropdown( {
 	block,
 	clientIds,
-	__experimentalSelectBlock,
 	children,
+	__experimentalSelectBlock,
 	__unstableDisplayLocation,
 	...props
 } ) {
 	// Get the client id of the current block for this menu, if one is set.
 	const currentClientId = block?.clientId;
-	const blockClientIds = Array.isArray( clientIds )
-		? clientIds
-		: [ clientIds ];
-	const count = blockClientIds.length;
-	const firstBlockClientId = blockClientIds[ 0 ];
+	const count = clientIds.length;
+	const firstBlockClientId = clientIds[ 0 ];
 	const {
 		firstParentClientId,
 		onlyBlock,