Backport wait_for_initialiazing_shards to cluster health API

Relates #27489

Author: dnhatn

core/src/main/java/org/elasticsearch/action/admin/cluster/health/ClusterHealthRequest.java

@@ -74,7 +74,7 @@ public ClusterHealthRequest(StreamInput in) throws IOException {
         if (in.readBoolean()) {
             waitForEvents = Priority.readFrom(in);
         }
-        if (in.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (in.getVersion().onOrAfter(Version.V_6_2_0)) {
             waitForNoInitializingShards = in.readBoolean();
         }
     }
@@ -106,7 +106,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(true);
             Priority.writeTo(waitForEvents, out);
         }
-        if (out.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (out.getVersion().onOrAfter(Version.V_6_2_0)) {
             out.writeBoolean(waitForNoInitializingShards);
         }
     }

rest-api-spec/src/main/resources/rest-api-spec/test/cluster.health/10_basic.yml

@@ -95,8 +95,8 @@
 ---
 "cluster health basic test, one index with wait for no initializing shards":
   - skip:
-      version: " - 6.99.99"
-      reason: "wait_for_no_initializing_shards is introduced in 7.0.0"
+      version: " - 6.1.99"
+      reason: "wait_for_no_initializing_shards is introduced in 6.2.0"
 
   - do:
       indices.create: