[BUILD] RemoteDeliveryErrorHandlingTest was unstable

As we did not await task execution the seond mail repository
reprocessing could be triggered while the first one was not
even started which would go undetected.

Strictier awaits does the trick
diff --git a/server/mailet/remote-delivery-integration-testing/src/test/java/org/apache/james/mailets/RemoteDeliveryErrorHandlingTest.java b/server/mailet/remote-delivery-integration-testing/src/test/java/org/apache/james/mailets/RemoteDeliveryErrorHandlingTest.java
index 96aab51..10ef070 100644
--- a/server/mailet/remote-delivery-integration-testing/src/test/java/org/apache/james/mailets/RemoteDeliveryErrorHandlingTest.java
+++ b/server/mailet/remote-delivery-integration-testing/src/test/java/org/apache/james/mailets/RemoteDeliveryErrorHandlingTest.java
@@ -249,22 +249,36 @@
                 .isEqualTo(1));
 
         // When we retry and temporary problem is not solved
-        given()
+        Object taskId = given()
             .spec(webAdminApi)
             .param("action", "reprocess")
             .param("queue", MailQueueFactory.SPOOL.asString())
             .param("processor", TRANSPORT_PROCESSOR)
-            .patch("/mailRepositories/" + REMOTE_DELIVERY_TEMPORARY_ERROR_REPOSITORY.getPath().urlEncoded() + "/mails");
+            .patch("/mailRepositories/" + REMOTE_DELIVERY_TEMPORARY_ERROR_REPOSITORY.getPath().urlEncoded() + "/mails")
+            .body()
+            .jsonPath()
+            .get("taskId");
+
+        given()
+            .spec(webAdminApi)
+            .get("/tests/" + taskId + "/await");
+
         awaitAtMostOneMinute
             .untilAsserted(() -> assertThat(jamesServer.getProbe(MailRepositoryProbeImpl.class)
                 .getRepositoryMailCount(REMOTE_DELIVERY_TEMPORARY_ERROR_REPOSITORY))
                 .isEqualTo(1));
-        given()
+        Object taskId2 = given()
             .spec(webAdminApi)
             .param("action", "reprocess")
             .param("queue", MailQueueFactory.SPOOL.asString())
             .param("processor", TRANSPORT_PROCESSOR)
-            .patch("/mailRepositories/" + REMOTE_DELIVERY_TEMPORARY_ERROR_REPOSITORY.getPath().urlEncoded() + "/mails");
+            .patch("/mailRepositories/" + REMOTE_DELIVERY_TEMPORARY_ERROR_REPOSITORY.getPath().urlEncoded() + "/mails")
+            .body()
+            .jsonPath()
+            .get("taskId");
+        given()
+            .spec(webAdminApi)
+            .get("/tests/" + taskId2 + "/await");
 
         // Then mail should be stored in permanent error repository
         awaitAtMostOneMinute