Task team assignment analogous to pin logic

Similar to the existing logic for pins, the team to which the creator belonged at the time of creation should also be saved for tasks.

Background:

If a team member (e.g. with the role of "assistant" or "external viewer") creates a task and later leaves the project, other team members can neither edit this task nor set it to "closed" - unless they have administrator rights.

In practice, this leads to unnecessary restrictions on further processing, especially in collaborative teams with limited rights.

This gap could be closed by automatic team assignment: All members of the same team would still have access to the tasks - just as is already the case with pins.