[ci] set at_device package as strict mode

bsp/stm32/stm32f407-rt-spark/.ci/attachconfig/online-packages/iot/at_devices.attach

@@ -1,3 +1,5 @@
+# scons: --strict
+
 CONFIG_PKG_USING_AT_DEVICE=y
 
 # Quectel M26/MC20