fix(tasks): update sub task relations in list view after they were created

Resolves https://kolaente.dev/vikunja/frontend/issues/3853

src/components/tasks/add-task.vue

@@ -149,13 +149,15 @@ async function addTask() {
 		await Promise.all(newTasks)
 
 		const taskRelationService = new TaskRelationService()
+		const allParentTasks = tasksToCreate.filter(t => t.parent !== null).map(t => t.parent)
 		const relations = tasksToCreate.map(async t => {
 			const createdTask = createdTasks[t.title]
 			if (typeof createdTask === 'undefined') {
 				return
 			}
 
-			if (t.parent === null) {
+			const isParent = allParentTasks.includes(t.title)
+			if (t.parent === null && !isParent) {
 				emit('taskAdded', createdTask)
 				return
 			}
@@ -175,6 +177,9 @@ async function addTask() {
 			// we're only emitting here so that the relation shows up in the project
 			emit('taskAdded', createdTask)
 
+			createdParentTask.relatedTasks[RELATION_KIND.SUBTASK] = [createdTask]
+			emit('taskAdded', createdParentTask)
+
 			return rel
 		})
 		await Promise.all(relations)

src/views/project/ProjectList.vue

@@ -241,9 +241,9 @@ function updateTaskList(task: ITask) {
 		loadTasks()
 	}
 	else {
-		tasks.value = [
+		allTasks.value = [
 			task,
-			...tasks.value,
+			...allTasks.value,
 		]
 	}