Update CreateAccountDemo.java

Signed-off-by: SimiHunjan <simi.hunjan.k@gmail.com>

Author: SimiHunjan

.github/examples/java/CreateAccountDemo.java

@@ -6,8 +6,8 @@
 public class CreateAccountDemo {
     public static void main(String[] args) throws Exception {
         // .env-provided
-        String operatorId = AccountId.fromString(System.getenv("OPERATOR_ID"));
-        String operatorKey = PrivateKey.fromString(System.getenv("OPERATOR_KEY"));
+        AccountId operatorId = AccountId.fromString(System.getenv("OPERATOR_ID"));
+        PrivateKey operatorKey = PrivateKey.fromString(System.getenv("OPERATOR_KEY"));
         String network = System.getenv().getOrDefault("HEDERA_NETWORK", "local"); // "local" for Solo
         String mirrorNodeUrl = System.getenv().getOrDefault(
             "MIRROR_NODE_URL",