Add the override modifier to InAppMessageActionUrlType toString

Author: emawby

OneSignalSDK/onesignal/core/src/main/java/com/onesignal/inAppMessages/InAppMessageActionUrlType.kt

@@ -24,7 +24,7 @@ enum class InAppMessageActionUrlType(
     REPLACE_CONTENT("replacement"),
     ;
 
-    fun toString(): String {
+    override fun toString(): String {
         return text
     }