PCD-6223: bump OVN_BASE to 25.09.4 to match rebase target

Author: c-nilesh1984

build-aux/build-common.sh

@@ -5,7 +5,7 @@ TEAMCITY_ROOT="$(pwd)"
 ROOT="$(pwd)/pf9-ovn"
 
 OVS_BASE="3.6.2"
-OVN_BASE="25.09.3"
+OVN_BASE="25.09.4"
 
 pf9_git_setup() {
     git config --global --add safe.directory '*'