ci: Use SDK v3.1.1 Tag

Broken with SDK v3.1.1+ and doesn't compile with v3.2

Author: ShineBrightMeow

west.yml

@@ -6,5 +6,5 @@ manifest:
     - name: sdk-nrf
       path: nrf
       url: https://github.com/nrfconnect/sdk-nrf.git
-      revision: v3.1-branch
+      revision: v3.1.1
       import: true