Fix fatal DB exception
Fix fatal DB exception

Follow-up I6c956738, which started trying to pull notification_timestamp out
of nowhere. Although EchoEvent::newFromRow may try to use this if it's set, it
wasn't previously getting selected and this is now causing exceptions.

Bug: T105890
Change-Id: I2dd9e268428d651813d8c43d85d54fc97634cd41

wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo