Remove redundant “Save” step when assigning users to a task

Currently, when assigning a user to a task, you have to click on their name(s) and then click “Save” to confirm. This extra step feels redundant.

Once the assignee(s) are selected, the assignment should be applied immediately, without needing to click “Save.” Especially since removing an assignee is already straightforward, this change would simplify the workflow.

This also happens when you need to remove someone.