samples: cellular: lwm2m_client: Support CoAP downloader

Support CoAP download protocol as the LwM2M engine
already has the stack enabled and this used to be
on by default.

Signed-off-by: Seppo Takalo <[email protected]>

Author: SeppoTakalo

samples/cellular/lwm2m_client/prj.conf

@@ -82,6 +82,7 @@ CONFIG_AT_MONITOR_HEAP_SIZE=512
 CONFIG_DOWNLOADER=y
 CONFIG_DOWNLOADER_STACK_SIZE=4096
 CONFIG_FOTA_DOWNLOAD=y
+CONFIG_DOWNLOADER_TRANSPORT_COAP=y
 
 # Application version
 CONFIG_MCUBOOT_IMGTOOL_SIGN_VERSION="1.0.0"