[nrf fromtree] bluetooth: smp: remove experimental from BT_GATT_AUTHORIZATION_CUSTOM

Removed the experimental status from the BT_GATT_AUTHORIZATION_CUSTOM
Kconfig option used in the Bluetooth Host GATT layer. This feature
has been present in Zephyr for almost a year without any issue reports
or API modifications.

Signed-off-by: Kamil Piszczek <[email protected]>
(cherry picked from commit f17431e)

Author: kapi-no

subsys/bluetooth/host/Kconfig.gatt

@@ -302,8 +302,7 @@ config DEVICE_NAME_GATT_WRITABLE_AUTHEN
 endif #BT_DEVICE_NAME_GATT_WRITABLE
 
 config BT_GATT_AUTHORIZATION_CUSTOM
-	bool "Custom authorization of GATT operations [EXPERIMENTAL]"
-	select EXPERIMENTAL
+	bool "Custom authorization of GATT operations"
 	help
 	  This option allows the user to define application-specific
 	  authorization logic for GATT operations that can be registered