Update time based triggering logic to guard against spam

Since the time based estimate takes recent usage into account we
could get a situation where the notification could trigger many
times. This CL makes it so the notification can only trigger at most
twice per charge cycle. The percentage based triggering remains
unaffected.

Test: SysUI Tests
Bug: 27567513
Change-Id: I81e29f96ac97b0d1a177e923c16d5f2800da404a