Make --task-id and --task-tag options valid only for table output in get-task command

[mountaindude]

If one or more task ids and/or task tags are specified there is a risk that this will filter out only parts of a task chain/tree.
Depending on how the tasks are chained together, what tags they have, what tags are specified in the --task-tag option etc, things may work just fine and a correct task tree is shown.

Things might go wrong though and only parts of a task chain/tree is included in the output shown.
Thus only allow those options when outputting to a screen or file table, at least for now.
If/when a good way of handling partial task trees is found, the above decision can be revisited.