Fixup Hub Client Exception Visibility

Signed-off-by: Alexander Twrdik <[email protected]>

src/main/java/de/privateaim/node_message_broker/common/hub/HubAnalysisNodesNotObtainable.java

@@ -3,7 +3,7 @@
 /**
  * Signals that analysis nodes could not be obtained from the hub core services.
  */
-public class HubAnalysisNodesNotObtainable extends RuntimeException {
+public final class HubAnalysisNodesNotObtainable extends RuntimeException {
     public HubAnalysisNodesNotObtainable(String message) {
         super(message);
     }

src/main/java/de/privateaim/node_message_broker/common/hub/HubCoreServerException.java

@@ -4,7 +4,7 @@
  * Signals that a request to a central Hub service has failed due to a server error.
  * An operation causing this error might be retryable.
  */
-public class HubCoreServerException extends RuntimeException {
+final class HubCoreServerException extends RuntimeException {
     public HubCoreServerException(String message) {
         super(message);
     }