Memfault SDK 1.26.1 update (#18)

Author: noahp

west.yml

@@ -13,4 +13,4 @@ manifest:
     - name: memfault-firmware-sdk
       url: https://github.com/memfault/memfault-firmware-sdk
       path: modules/lib/memfault-firmware-sdk
-      revision: 1.26.0
+      revision: 1.26.1