Use a single text view for count and date of calls.

This further reduces the number of views needed to render the call log.

At the same time, fix a few minor issues that are needed for pixel
perfect UI:
- Do not show the text when the item is new.
- Instead, for new items, highlight the date in the color associated
  with the item (blue for voicemail, red for missed calls).
- Do not put a separating slash between the count and the date.

Bug: 5099652
Change-Id: I18b71463e7398f00f0fe8fecbeb334b67d618312