[Transform] re-enable BWC after backport of #70139 (#70218)

finish backport of #70139: adapt versions and re-enable BWC

build.gradle

@@ -189,8 +189,8 @@ tasks.register("verifyVersions") {
  * after the backport of the backcompat code is complete.
  */
 
-boolean bwc_tests_enabled = false
-String bwc_tests_disabled_issue = "https://github.com/elastic/elasticsearch/pull/70203" /* place a PR link here when committing bwc changes */
+boolean bwc_tests_enabled = true
+String bwc_tests_disabled_issue = "" /* place a PR link here when committing bwc changes */
 /*
  * 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

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/TransformStats.java

@@ -151,7 +151,7 @@ public class TransformStats implements Writeable, ToXContentObject {
         if (out.getVersion().onOrAfter(Version.V_7_4_0)) {
             out.writeString(id);
             // 7.13 introduced the waiting state, in older version report the state as started
-            if (out.getVersion().before(Version.V_8_0_0) && state.equals(State.WAITING)) {   // TODO: V_7_13_0
+            if (out.getVersion().before(Version.V_7_13_0) && state.equals(State.WAITING)) {
                 out.writeEnum(State.STARTED);
             } else {
                 out.writeEnum(state);

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/transform/transforms/TransformStatsTests.java

@@ -143,7 +143,7 @@ public class TransformStatsTests extends AbstractSerializingTestCase<TransformSt
                 output.setVersion(Version.V_7_12_0);
                 stats.writeTo(output);
                 try (StreamInput in = output.bytes().streamInput()) {
-                    in.setVersion(Version.V_8_0_0); // TODO: V_7_13_0
+                    in.setVersion(Version.V_7_13_0);
                     TransformStats statsFromOld = new TransformStats(in);
                     assertThat(statsFromOld.getState(), equalTo(STARTED));
                 }