Overwriting files in WAR with AMP broken since v5.3.0 - required for e.g. applying hotfixes

[todorinskiz]

Caused by: https://github.com/xenit-eu/alfresco-docker-gradle-plugin/pull/204/files#diff-e388b16e7e9b41aaf276a70a19a4d9b82478b1ad1ffb1e48922accfd30926942R28

Reproducer build.gradle:

plugins {
    id "base"
    id "eu.xenit.docker-alfresco" version "5.3.0"
}

dependencies {
    baseAlfrescoWar "org.alfresco:content-services:6.1.1@war"
    alfrescoAmp 'eu.xenit.alfresco:alfresco-hotfix-MNT-20557:1.0.2@amp'
}

task alfrescoWar_patched(type: eu.xenit.gradle.docker.alfresco.tasks.MergeWarsTask) {
    group "alfresco"
////  WONT WORK
//    duplicatesStrategy = DuplicatesStrategy.
    addInputWar(tasks.applyAlfrescoAmp)
    addInputWar(tasks.applyAlfrescoDE)
    addInputWar(tasks.applyAlfrescoSM)

//  Adding the base war last ensures that the files applied with the previous tasks are not overwritten
//  by the base war.
    addInputWar(project.provider({project.configurations.baseAlfrescoWar.singleFile}))
}

dockerAlfresco {
    baseImage = "docker.io/xenit/alfresco-repository-skeleton:6.1.1"
    dockerBuild {
        repository = 'hub.xenit.eu/alfresco-docker-gradle-plugin-reproducer/alfresco'
    }
}

createDockerFile {
    group 'docker'
}

repositories {
    mavenCentral()
    maven {
        url 'https://artifactory.xenit.eu/artifactory/libs-release'
        credentials {
            username property("eu.xenit.artifactory.username")
            password property("eu.xenit.artifactory.password")
        }
    }
}```

[vierbergenlars]

Well, it appears that this issue is already fixed in master, but I added an integration test anyways (and tested that it fails with 5.3.0)