Fix similar flaky await patterns in MQTT transport tests

doGet/doGetAsyncTyped assert HTTP 200 internally, so any non-200 response
throws AssertionError which Awaitility re-throws immediately instead of
continuing to poll.

Add .ignoreExceptions() to three additional await() polling loops that
call HTTP helpers:
- AbstractMqttV5ClientSparkplugAttributesTest: two doGetAsyncTyped calls
  polling for attribute keys after NBIRTH/DBIRTH
- AbstractMqttAttributesIntegrationTest: doGetAsyncTyped polling for
  attribute values after client publish

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/attributes/AbstractMqttAttributesIntegrationTest.java

@@ -420,6 +420,7 @@ public abstract class AbstractMqttAttributesIntegrationTest extends AbstractMqtt
 
         Awaitility.await()
                 .atMost(10, TimeUnit.SECONDS)
+                .ignoreExceptions()
                 .until(() -> {
                     List<Map<String, Object>> attributes = doGetAsyncTyped(attributeValuesUrl, new TypeReference<>() {
                     });

application/src/test/java/org/thingsboard/server/transport/mqtt/sparkplug/attributes/AbstractMqttV5ClientSparkplugAttributesTest.java

@@ -468,6 +468,7 @@ public abstract class AbstractMqttV5ClientSparkplugAttributesTest extends Abstra
         AtomicReference<List<String>> actualKeys = new AtomicReference<>();
         await(alias + SparkplugMessageType.NBIRTH.name())
                 .atMost(40, TimeUnit.SECONDS)
+                .ignoreExceptions()
                 .until(() -> {
                     actualKeys.set(doGetAsyncTyped(urlTemplate, new TypeReference<>() {
                     }));
@@ -483,6 +484,7 @@ public abstract class AbstractMqttV5ClientSparkplugAttributesTest extends Abstra
         AtomicReference<List<String>> actualKeys = new AtomicReference<>();
         await(alias + SparkplugMessageType.DBIRTH.name())
                 .atMost(40, TimeUnit.SECONDS)
+                .ignoreExceptions()
                 .until(() -> {
                     actualKeys.set(doGetAsyncTyped(urlTemplate, new TypeReference<>() {
                     }));