Rollback SourceType#NONE

Author: mk868

java/src/org/openqa/selenium/interactions/SourceType.java

@@ -18,22 +18,23 @@
 package org.openqa.selenium.interactions;
 
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 /** One of the allowing types for an {@link InputSource}. */
 @NullMarked
 public enum SourceType {
   KEY("key"),
-  NONE("none"),
+  NONE(null),
   POINTER("pointer"),
   WHEEL("wheel");
 
-  private final String type;
+  private final @Nullable String type;
 
-  SourceType(String type) {
+  SourceType(@Nullable String type) {
     this.type = type;
   }
 
-  public String getType() {
+  public @Nullable String getType() {
     return type;
   }
 }