[JENKINS-48365] Restrict InstallUtil#NEW_INSTALL_VERSION

core/src/main/java/jenkins/install/InstallUtil.java

@@ -70,6 +70,7 @@ public class InstallUtil {
     private static final Logger LOGGER = Logger.getLogger(InstallUtil.class.getName());
 
     // tests need this to be 1.0
+    @Restricted(NoExternalUse.class)
     public static final VersionNumber NEW_INSTALL_VERSION = new VersionNumber("1.0");
     private static final VersionNumber FORCE_NEW_INSTALL_VERSION = new VersionNumber("0.0");