Dragging a subtask to a section and back causes the subtask to disappear

[Riksu9000]

Describe the bug
Dragging a subtask to a section and back on the parent task causes the subtask to disappear. Also the dropdown button is visible on the parent task while there are no subtasks.

To Reproduce
Steps to reproduce the behavior:

1. Create a section
2. Create a task with a subtask
3. Drag the subtask to the section
4. Drag the task back on the parent task

Expected behavior
The task shouldn't disappear and the dropdown button should not be visible while there are no subtasks.

Screenshots
https://github.com/alainm23/planify/assets/37774658/9d0d3df2-9033-4299-adbc-12e7a93da1eb

Desktop (please complete the following information):

• Fedora, planify 15a598e

Additional context
This issue might be related to #1244.