`cylc tui ID` should not provide the "stop all" option when filtered

[hjoliver]

(A user was surprised when "stop all" stopped ~60 worklfows, despite starting TUI for a specific one).

TUI can currently display

• all running workflows (cylc tui)
• a single running workflow (cylc tui ID)

In both cases, stop all at the trunk (username) level of the tree stops all of the user's workflows.

When displaying a single workflow we should rebase the tree on workflow ID so to that "stop all" is not available.

If in future we support displaying a subset of all workflows (e.g. cylc tui "nwp*"), then "stop all" should just stop those.

(An alternative might be to ask for confirmation before stopping ALL workflows, but IMO better just to stop all the workflows that TUI is displaying).

[oliver-sanders]

Ok, we should only display the "stop all" option if there is no workflow filter in play.

If in future we support displaying a subset of all workflows (e.g. cylc tui "nwp*"), then "stop all" should just stop those.

Agreed, but may be harder to implement.