update bug report notification title

Since the existing notification style sets maxLines to 2, the title was
being truncated and the percentage was thus not visible to the user.

As recommended by UX, we are updating the string so that it is no longer
truncated and the percentage text is visible.

Screenshots:
Before - https://screenshot.googleplex.com/9U6RKuMcnECQ3pV
After - https://screenshot.googleplex.com/8U9NCJHhR5qkRCD

BUG: 198747050
Change-Id: I2b94cc65e2b9c3af860dd35532e1060814f6a68e
(cherry picked from commit 262e835016e340e5fd7b5eb00b7ac6579ca127ae)