fixed sas credentials in iot hub node

(cherry picked from commit 36ff1a8f9e853da7b5f1d0bf3e564b37ea0d92bc)

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/credentials/CertPemCredentials.java

@@ -56,7 +56,7 @@ import java.security.spec.PKCS8EncodedKeySpec;
 public class CertPemCredentials implements ClientCredentials {
     private static final String TLS_VERSION = "TLSv1.2";
 
-    private String caCert;
+    protected String caCert;
     private String cert;
     private String privateKey;
     private String password;

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/mqtt/azure/AzureIotHubSasCredentials.java

@@ -40,8 +40,7 @@ import java.security.cert.X509Certificate;
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class AzureIotHubSasCredentials extends CertPemCredentials {
     private String sasKey;
-    private String caCert;
-    
+
     @Override
     public SslContext initSslContext() {
         try {