samples: lwm2m_client: Increase AT monitor heap

Sometimes during "lte offline" or during FOTA the
AT monitor module may run out of heap space.

Increase the default AT monitor heap to same as with
assis-cell overlay.

Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>

samples/cellular/lwm2m_client/overlay-assist-cell.conf

@@ -11,8 +11,6 @@ CONFIG_LWM2M_RW_SENML_CBOR_SUPPORT=y
 CONFIG_ZCBOR=y
 CONFIG_ZCBOR_CANONICAL=y
 CONFIG_LWM2M_RW_SENML_CBOR_RECORDS=35
-# Increase AT monitor heap because %NCELLMEAS notifications can be large
-CONFIG_AT_MONITOR_HEAP_SIZE=512
 
 # AVSystem CDM-665 workaround: force object version reporting.
 CONFIG_LWM2M_CONNMON_OBJECT_VERSION_1_3=y

samples/cellular/lwm2m_client/prj.conf

@@ -76,6 +76,7 @@ CONFIG_HEAP_MEM_POOL_SIZE=16384
 CONFIG_MAIN_STACK_SIZE=4096
 CONFIG_LWM2M_ENGINE_STACK_SIZE=3072
 CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
+CONFIG_AT_MONITOR_HEAP_SIZE=512
 
 # Allow FOTA downloads using download-client
 CONFIG_DOWNLOAD_CLIENT=y