[2.7.0 target] Fixes error not properly being caught (#5798) (#5806)

Fixes error not properly being caught (#5798)

Update Utils.java

(cherry picked from commit 6caf20c)

src/main/java/ch/njol/skript/util/Utils.java

@@ -199,7 +199,7 @@ public static Class<?>[] getClasses(Plugin plugin, String basePackage, String...
 			for (String c : classNames) {
 				try {
 					classes.add(Class.forName(c, true, plugin.getClass().getClassLoader()));
-				} catch (ClassNotFoundException ex) {
+				} catch (ClassNotFoundException | NoClassDefFoundError ex) {
 					Skript.exception(ex, "Cannot load class " + c);
 				} catch (ExceptionInInitializerError err) {
 					Skript.exception(err.getCause(), "class " + c + " generated an exception while loading");