Check the voicemail IDs as opposed to the whole URI.

When determining whether to notify for a particular voicemail, check the
voicemail IDs instead of the whole URI since sometimes the URI will
include query parameters and sometimes not so we don't want to do a
direct string comparison. Doing a direct comparison was causing a bug
where the sound and vibration of the new notification would be suppressed.

Bug: 19716109
Change-Id: I7a33b4d3bcd9ca707db9462fcebfec27fd5f8a74