Remove _primary preference from get/mget requests (opensearch-project#391)

Signed-off-by: Suraj Singh <surajrider@gmail.com>

Author: dreamer-89

src/main/java/org/opensearch/geospatial/ip2geo/dao/DatasourceDao.java

@@ -217,7 +217,7 @@ public void deleteDatasource(final Datasource datasource) {
      * @throws IOException exception
      */
     public Datasource getDatasource(final String name) throws IOException {
-        GetRequest request = new GetRequest(DatasourceExtension.JOB_INDEX_NAME, name).preference(Preference.PRIMARY.type());
+        GetRequest request = new GetRequest(DatasourceExtension.JOB_INDEX_NAME, name);
         GetResponse response;
         try {
             response = StashedThreadContext.run(client, () -> client.get(request).actionGet(clusterSettings.get(Ip2GeoSettings.TIMEOUT)));
@@ -244,7 +244,7 @@ public Datasource getDatasource(final String name) throws IOException {
      * @param actionListener the action listener
      */
     public void getDatasource(final String name, final ActionListener<Datasource> actionListener) {
-        GetRequest request = new GetRequest(DatasourceExtension.JOB_INDEX_NAME, name).preference(Preference.PRIMARY.type());
+        GetRequest request = new GetRequest(DatasourceExtension.JOB_INDEX_NAME, name);
         StashedThreadContext.run(client, () -> client.get(request, new ActionListener<>() {
             @Override
             public void onResponse(final GetResponse response) {
@@ -282,7 +282,6 @@ public void getDatasources(final String[] names, final ActionListener<List<Datas
             client,
             () -> client.prepareMultiGet()
                 .add(DatasourceExtension.JOB_INDEX_NAME, names)
-                .setPreference(Preference.PRIMARY.type())
                 .execute(createGetDataSourceQueryActionLister(MultiGetResponse.class, actionListener))
         );
     }

src/test/java/org/opensearch/geospatial/ip2geo/dao/DatasourceDaoTests.java

@@ -206,7 +206,6 @@ private Datasource setupClientForGetRequest(final boolean isExist, final Runtime
             GetRequest request = (GetRequest) actionRequest;
             assertEquals(datasource.getName(), request.id());
             assertEquals(DatasourceExtension.JOB_INDEX_NAME, request.index());
-            assertEquals(Preference.PRIMARY.type(), request.preference());
             GetResponse response = getMockedGetResponse(isExist ? datasource : null);
             if (exception != null) {
                 throw exception;
@@ -264,7 +263,6 @@ public void testGetDatasources_whenValidInput_thenSucceed() {
             assertTrue(actionRequest instanceof MultiGetRequest);
             MultiGetRequest request = (MultiGetRequest) actionRequest;
             assertEquals(2, request.getItems().size());
-            assertEquals(Preference.PRIMARY.type(), request.preference());
             for (MultiGetRequest.Item item : request.getItems()) {
                 assertEquals(DatasourceExtension.JOB_INDEX_NAME, item.index());
                 assertTrue(datasources.stream().filter(datasource -> datasource.getName().equals(item.id())).findAny().isPresent());