Enable BWC tests after backporting token, api key service status change

Enable BWC tests after backporting token, api key service status change.
Addressed TODO to update the version to 7.1.0.

Closes elastic#38535

build.gradle

@@ -159,8 +159,8 @@ task verifyVersions {
  * the enabled state of every bwc task. It should be set back to true
  * after the backport of the backcompat code is complete.
  */
-final boolean bwc_tests_enabled = false
-final String bwc_tests_disabled_issue = "https://github.com/elastic/elasticsearch/pull/38687" /* place a PR link here when committing bwc changes */
+final boolean bwc_tests_enabled = true
+final String bwc_tests_disabled_issue = "" /* place a PR link here when committing bwc changes */
 if (bwc_tests_enabled == false) {
   if (bwc_tests_disabled_issue.isEmpty()) {
     throw new GradleException("bwc_tests_disabled_issue must be set when bwc_tests_enabled == false")

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/SecurityFeatureSetUsage.java

@@ -43,7 +43,7 @@ public SecurityFeatureSetUsage(StreamInput in) throws IOException {
         realmsUsage = in.readMap();
         rolesStoreUsage = in.readMap();
         sslUsage = in.readMap();
-        if (in.getVersion().onOrAfter(Version.V_8_0_0)) { // TODO change the version to V_7_1_0 on backporting
+        if (in.getVersion().onOrAfter(Version.V_7_1_0)) {
             tokenServiceUsage = in.readMap();
             apiKeyServiceUsage = in.readMap();
         }