Redundant code optimization for GattService event

Redundant code optimization for GattService event

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

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

[Problem] When below interface removed, check the unnecessary condition
org.bluez.GattDescriptor1
org.bluez.GattCharacteristic1
[Cause & Measure] When Characteristic or Descriptor is removed,
    checking watcher list is not required.
    Just check it for org.bluez.GattService1 interface
[Checking Method] Connection with iOS GM

[Team] Basic Connection
[Developer] Injun Yang
[Solution company] Samsung
[Change Type] Specification change

Change-Id: Id587ffe489526c75cdfd9192c721a03a3eebcd9d