Stop using deprecated JavaConventions.validateJavaTypeName method

The replacement one has one more parameter previewEnabled but it's fine
to pass null to have it disabled as per javadoc.

e4tools/bundles/org.eclipse.e4.tools/src/org/eclipse/e4/internal/tools/wizards/classes/AbstractNewClassPage.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2010, 2017 BestSolution.at and others.
+ * Copyright (c) 2010, 2024 BestSolution.at and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -517,7 +517,7 @@ public IStatus validate(String name) {
 						Messages.AbstractNewClassPage_NameMustBeQualified);
 			}
 
-			return JavaConventions.validateJavaTypeName(name, JavaCore.VERSION_1_3, JavaCore.VERSION_1_3);
+			return JavaConventions.validateJavaTypeName(name, JavaCore.VERSION_1_3, JavaCore.VERSION_1_3, null);
 		}
 	}