set_advertising returns in_progress error even if the restart is scheduled by le...

set_advertising returns in_progress error even if the restart is scheduled by le connection.

le_discovering should be set before remove_watch is called

[Model] 5.5
[BinType] AP
[Customer] OPEN

[Issue#] P200824-01952
[Request] PLM
[Occurrence Version] R825USQE1BTH8

[Problem] set_advertising fails
[Cause & Measure] advertising is already stopped by le connection.
  And the restart is scheduled with 300ms delay.
  set_advertising returns in_progress error even if the restart is scheduled
  by le connection.
[Checking Method] Try to stop advertising right after le is connected.

[Team] Bluetooth
[Developer] Deokhyun Kim
[Solution company] Samsung
[Change Type] Specification change

Change-Id: I7fef2e0b5fba1219dfe8f02b223d870450ccb651
Signed-off-by: Deokhyun Kim <dukan.kim@samsung.com>
Signed-off-by: Wootak Jung <wootak.jung@samsung.com>