Fixed that the duplicated UserHandle not to be added when it's delivered while booting process

Fixed that the duplicated missed call notification not to be registered
in multi-user environment by not adding the duplicated UserHandle

Bug: 214485291
Test: Reboot the device in multi-user environment when missed call notification is already exist

Signed-off-by: Junyeong Bak <junyeong.bak@samsung.com>
Change-Id: I70a309250eb926d9d9aa888d4aa4fd6579fdfe95