Allow Subtask creation at task creation in ios & MacOS

Right now in iOS, when creating a task it’s not possible to create Subtask straight in the creating window. Plz change that and allow the possibility to create Subtask right away

There’s a similar issue in macOS I believe, especially when creating a task straight into and already existant goal list, where only task title and description is possible to write in. Possibility to write in MacOS Subtasks there would be useful too <3