Drop explicit phase for flatten:clean

Author: pzygielo

mq/distribution/pom.xml

@@ -2,7 +2,7 @@
 <!--
 
     Copyright (c) 2011, 2020 Oracle and/or its affiliates. All rights reserved.
-    Copyright (c) 2022, 2024 Contributors to Eclipse Foundation. All rights reserved.
+    Copyright (c) 2022, 2025 Contributors to Eclipse Foundation. All rights reserved.
 
     This program and the accompanying materials are made available under the
     terms of the Eclipse Public License v. 2.0, which is available at
@@ -86,7 +86,6 @@
 					</execution>
 					<execution>
 						<id>flatten.clean</id>
-						<phase>clean</phase>
 						<goals>
 							<goal>clean</goal>
 						</goals>