To evaluate whether a user is subscribed to a list or unsubscribed you need to take into account
the status of the current subscription and not only the global status. To be unsubscribed you are
either globally or per list unsubscribed. To be subscribed you need to be globally and per list
subscribed
[MAILPOET-4487]
We agreed that we can use WP translation functions directly.
This one was probably some leftover which remained in the file after merging branches.
The file was missing use statement so this was causing an error.
[MAILPOET-4551]
Although it doesn't make senses to select a segment with 0 subscribers
directly from the dropdown, we allow users to click a "view subscribers"
link or, with MAILPOET-4244, click a badge to see all the subscribers of
that segment. The UI on the subscribers page indicates which segment is
selected by selecting it in the dropdown.
If we exclude lists with 0 subscribers (or 0 calculated
subscribers), the filter selection is blank and the user has no way of
knowing what filter is being applied. By including these empty lists
we're giving users a way of knowing why there are 0 subscribers being
shown.
MAILPOET-4244
