Fix versions and breaking API changes (opensearch-project#17031)

Signed-off-by: Andriy Redko <andriy.redko@aiven.io>

Author: reta

rest-api-spec/src/main/resources/rest-api-spec/test/search_shards/20_slice.yml

@@ -1,7 +1,7 @@
 ---
 "Search shards with slice specified in body":
   - skip:
-      version: " - 2.99.99"
+      version: " - 2.18.99"
       reason: "Added slice body to search_shards in 2.19"
   - do:
       indices.create:

server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequest.java

@@ -80,7 +80,7 @@ public ClusterSearchShardsRequest(StreamInput in) throws IOException {
         preference = in.readOptionalString();
 
         indicesOptions = IndicesOptions.readIndicesOptions(in);
-        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+        if (in.getVersion().onOrAfter(Version.V_2_19_0)) {
             boolean hasSlice = in.readBoolean();
             if (hasSlice) {
                 sliceBuilder = new SliceBuilder(in);
@@ -95,7 +95,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalString(routing);
         out.writeOptionalString(preference);
         indicesOptions.writeIndicesOptions(out);
-        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_2_19_0)) {
             if (sliceBuilder != null) {
                 out.writeBoolean(true);
                 sliceBuilder.writeTo(out);