chore: automated PR to update VHDVersion for 202511.12.0 VHD (#7363)

Co-authored-by: aks-node-assistant[bot] <190555641+aks-node-assistant[bot]@users.noreply.github.com>

Author: aks-node-assistant[bot]

pkg/agent/datamodel/linux_sig_version.json

@@ -1,3 +1,3 @@
 {
-  "version": "202511.07.0"
+  "version": "202511.12.0"
 }