fix: prevent hotswap failure if class is not found (#20549)

References #20389

Author: mcollovati

flow-server/src/main/java/com/vaadin/flow/hotswap/Hotswapper.java

@@ -469,7 +469,7 @@ private static Class<?> resolveClass(String className) {
         try {
             return Class.forName(className, false,
                     Thread.currentThread().getContextClassLoader());
-        } catch (ClassNotFoundException e) {
+        } catch (ClassNotFoundException | NoClassDefFoundError e) {
             LOGGER.debug("Cannot resolve class {}", className, e);
         }
         return null;