fix: Alter handling of cases where key value is not present (#13174) (#…

…13200)

Fixes: #13004
Fixes: #13173

Co-authored-by: Tatu Lund <tatu@vaadin.com>

flow-server/src/main/java/com/vaadin/flow/component/Key.java

@@ -2696,6 +2696,12 @@ public interface Key extends Serializable {
      */
     Key SUSPEND = Key.of("Suspend");
 
+    /**
+     * This value is reserved for corner cases of no key value present in event
+     * e.g. when browser autosuggest is used.
+     */
+    Key NONE = Key.of("None");
+
     /**
      * Returns a {@link Key} instance for a printable representation of the key.
      * <p>
@@ -2713,9 +2719,8 @@ public interface Key extends Serializable {
      * @return the {@link Key} instance
      */
     static Key of(String key, String... additionalKeys) {
-        Objects.requireNonNull(key);
-        if ("".equals(key)) {
-            throw new IllegalArgumentException("'key' cannot be empty");
+        if (key == null || "".equals(key)) {
+            return NONE;
         }
         List<String> keys = new ArrayList<>();
         keys.add(key);