Re-enable bwc tests after backporting #70094 to 7.x branch. (#70304)

Author: martijnvg

build.gradle

@@ -189,9 +189,9 @@ tasks.register("verifyVersions") {
  * after the backport of the backcompat code is complete.
  */
 
-boolean bwc_tests_enabled = false
+boolean bwc_tests_enabled = true
 // place a PR link here when committing bwc changes:
-String bwc_tests_disabled_issue = "https://github.com/elastic/elasticsearch/pull/70094"
+String bwc_tests_disabled_issue = ""
 /*
  * FIPS 140-2 behavior was fixed in 7.11.0. Before that there is no way to run elasticsearch in a
  * JVM that is properly configured to be in fips mode with BCFIPS. For now we need to disable

server/src/main/java/org/elasticsearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateAction.java

@@ -38,7 +38,7 @@ public static class Request extends MasterNodeRequest<Request> {
 
         public Request(StreamInput in) throws IOException {
             super(in);
-            if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (in.getVersion().onOrAfter(Version.V_7_13_0)) {
                 names = in.readStringArray();
             } else {
                 names = new String[] {in.readString()};
@@ -71,7 +71,7 @@ public String[] names() {
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             super.writeTo(out);
-            if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (out.getVersion().onOrAfter(Version.V_7_13_0)) {
                 out.writeStringArray(names);
             } else {
                 out.writeString(names[0]);

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

@@ -581,7 +581,7 @@ private void wipeCluster() throws Exception {
                         .collect(Collectors.toList());
                     // Ideally we would want to check the version of the elected master node and
                     // send the delete request directly to that node.
-                    if (nodeVersions.stream().allMatch(version -> version.onOrAfter(Version.V_8_0_0))) {
+                    if (nodeVersions.stream().allMatch(version -> version.onOrAfter(Version.V_7_13_0))) {
                         try {
                             adminClient().performRequest(new Request("DELETE", "_index_template/" + String.join(",", names)));
                         } catch (ResponseException e) {