[QS] Update hotspot tile secondary text (data saver)

Updating the secondary text to show a different message when data saver
is enabled (to explain to the user why they can't toggle the tile).

Also collapsed double ternary to make it a bit easier to read.

Test: Visually
Bug: 33003328
Change-Id: I8a98f95c60ec9dcbe5899e87e29759e8d377b106