Fix : GATT service changed event is not invoked

Fix : GATT service changed event is not invoked

[Model] All
[BinType] AP
[Customer] OPEN

[Issue#] N/A
[Request] Internal
[Occurrence Version] N/A

[Problem] gatt service changed event is not invoked
[Cause & Measure] gatt connection status is not updated on GATT server role
[Checking Method] LE connected as slave (ANCS connection) > Launch iOG GM

[Team] Convergence BT
[Developer] Injun Yang
[Solution company] Samsung
[Change Type] Specification change

Change-Id: I0721b59693d94869d16c272bc671d035f4b4fcc6