Improve appearance of on hold label for tasks with no on_hold_duration

[lowellrex]

Currently if a task is on hold it displays text that indicates how many days it has been on hold out of how many days total (8 of 30, for example). This makes sense for tasks that have a hold duration, but results in nonsense for tasks with no on_hold_duration (8 of ?). We should display only the number of days a task has been on hold if there is no on_hold_duration.

Acceptance criteria

• Days on hold value does not include "of ?" text for tasks that do not have an on_hold_duration

Before	After