Added check for user info is not null

user's actual state might have changed by the time the broadcast is
received, so added a null check.

Bug: 237413499
Test: atest HandlerThreadingDomainTest LocationTimeZoneProviderControllerTest LocationTimeZoneProviderTest ZoneInfoDbTimeZoneProviderEventPreProcessorTest

Change-Id: I79087a3e83a51b81568bdb6ff5540ee78b51b91a
Merged-In: Ieacbb35e522b35353c96de1f162a8a71388b4b04
(cherry pick from commit 799c6528)