Fix MP tests

Author: nielsbauman

test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java

@@ -2794,7 +2794,7 @@ private Collection<String> getProjectIds(RestClient client) throws IOException {
     protected void cleanUpProjects() throws IOException {
         final var projectIds = getProjectIds(adminClient());
         for (String projectId : projectIds) {
-            if (projectId.equals(ProjectId.DEFAULT.id())) {
+            if (projectId.equals(ProjectId.DEFAULT.id()) || projectId.equals(activeProject) || extraProjects.contains(projectId)) {
                 continue;
             }
             deleteProject(projectId);

x-pack/plugin/security/qa/multi-project/build.gradle

@@ -8,3 +8,7 @@ tasks.named('javaRestTest') {
   usesDefaultDistribution("to be triaged")
   it.onlyIf("snapshot build") { buildParams.snapshotBuild }
 }
+
+tasks.withType(Test).configureEach {
+  it.systemProperty "test.multi_project.enabled", true
+}

x-pack/qa/multi-project/core-rest-tests-with-multiple-projects/build.gradle

@@ -82,4 +82,6 @@ tasks.named("yamlRestTest").configure {
     blacklist += [];
   }
   systemProperty 'tests.rest.blacklist', blacklist.join(',')
+
+  systemProperty "test.multi_project.enabled", true
 }

x-pack/qa/multi-project/xpack-rest-tests-with-multiple-projects/build.gradle

@@ -164,4 +164,5 @@ tasks.named("yamlRestTest").configure {
     blacklist += [];
   }
   systemProperty 'tests.rest.blacklist', blacklist.join(',')
+  systemProperty "test.multi_project.enabled", true
 }