Post-migration Experience: Adds the placeholder task list (#39593)

* Add the placeholder Migration task list

* changelog

* Update the tasklist name to match calypso's

---------

Co-authored-by: Valter Lorran <valter.lorran@automattic.com>

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/11130571297

Upstream-Ref: Automattic/jetpack@3583df8

vendor/automattic/jetpack-mu-wpcom/CHANGELOG.md

@@ -11,6 +11,7 @@ This is an alpha version! The changes listed here are not final.
 
 ### Added
 - Adds JSON translation files
+- Adds the placeholder task list for the Migration flow
 - Global Styles: add a Help Link to premium styles limitation message
 
 ### Changed

vendor/automattic/jetpack-mu-wpcom/src/features/launchpad/launchpad-task-definitions.php

@@ -802,6 +802,13 @@ function wpcom_launchpad_get_task_definitions() {
 				return site_url( '/wp-admin/admin.php?page=wc-admin&task=launch_site' );
 			},
 		),
+		'migrating_site'                  => array(
+			'get_title'            => function () {
+				return __( 'Migrating the site', 'jetpack-mu-wpcom' );
+			},
+			'is_complete_callback' => 'wpcom_launchpad_is_task_option_completed',
+			'is_visible_callback'  => '__return_true',
+		),
 	);
 
 	$extended_task_definitions = apply_filters( 'wpcom_launchpad_extended_task_definitions', array() );

vendor/automattic/jetpack-mu-wpcom/src/features/launchpad/launchpad.php

@@ -315,6 +315,14 @@ function wpcom_launchpad_get_task_list_definitions() {
 				'woo_launch_site',
 			),
 		),
+		'post-migration'          => array(
+			'get_title' => function () {
+				return __( 'Site migration', 'jetpack-mu-wpcom' );
+			},
+			'task_ids'  => array(
+				'migrating_site',
+			),
+		),
 	);
 
 	$extended_task_list_definitions = apply_filters( 'wpcom_launchpad_extended_task_list_definitions', array() );