Update version for ClusterMetadataManifest after 2.15 backport (opensearch-project#14226)

Signed-off-by: Shivansh Arora <[email protected]>

Author: shiv0408

server/src/main/java/org/opensearch/gateway/remote/ClusterMetadataManifest.java

@@ -516,7 +516,7 @@ public ClusterMetadataManifest(StreamInput in) throws IOException {
         this.indices = Collections.unmodifiableList(in.readList(UploadedIndexMetadata::new));
         this.previousClusterUUID = in.readString();
         this.clusterUUIDCommitted = in.readBoolean();
-        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+        if (in.getVersion().onOrAfter(Version.V_2_15_0)) {
             this.codecVersion = in.readInt();
             this.uploadedCoordinationMetadata = new UploadedMetadataAttribute(in);
             this.uploadedSettingsMetadata = new UploadedMetadataAttribute(in);
@@ -690,7 +690,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeCollection(indices);
         out.writeString(previousClusterUUID);
         out.writeBoolean(clusterUUIDCommitted);
-        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_2_15_0)) {
             out.writeInt(codecVersion);
             uploadedCoordinationMetadata.writeTo(out);
             uploadedSettingsMetadata.writeTo(out);