[nrf noup] Mark CHIP_ICD_LIT_SUPPORT experimental

LIT functionality is provisional for Matter 1.3.
Set it as experimental for now.

Signed-off-by: Maciej Baczmanski <maciej.baczmanski@nordicsemi.no>

Author: maciejbaczmanski

config/zephyr/Kconfig

@@ -401,6 +401,7 @@ config CHIP_ICD_LIT_SUPPORT
 	bool "Intermittenly Connected Device Long Idle Time support"
 	select CHIP_ICD_CHECK_IN_SUPPORT
 	select CHIP_ICD_UAT_SUPPORT
+	select EXPERIMENTAL
 	help
 	  Enables the Intermittently Connected Device Long Idle Time support in Matter.
 	  It also selects the ICD Check-In and UAT features support that are mandatory for LIT device.