Adjust wording of preference link

Per UX team request, adjust the wording of the preference link and
include the count of applications in the text.

Note this differs from the exact wording requested by the UX team:
* All other labels on that section of the preferences form are in
  sentence case rather than title case, so the same is done here
* The number is inserted in the obvious place.

Bug: 55716
Change-Id: Id1690f3e12741149107bd43051598e75a65e3fed