Adjust Functions getters to be Kotlin source compatible

Author: emilypgoogle

firebase-functions/src/main/java/com/google/firebase/functions/HttpsCallableResult.kt

@@ -16,15 +16,12 @@ package com.google.firebase.functions
 /** The result of calling a HttpsCallableReference function. */
 public class HttpsCallableResult
 internal constructor( // The actual result data, as generic types decoded from JSON.
-private val data: Any?) {
   /**
-   * Returns the data that was returned from the Callable HTTPS trigger.
+   * The data that was returned from the Callable HTTPS trigger.
    *
    * The data is in the form of native Java objects. For example, if your trigger returned an array,
    * this object would be a List<Object>. If your trigger returned a JavaScript object with keys and
    * values, this object would be a Map<String, Object>.
    */
-  public fun getData(): Any? {
-    return data
-  }
-}
+  public val data: Any?
+) {}