Fix system info when ES throw errors (geonetwork#7413)

In the administration info page if ES connection throws an exception the page doesn't display any other info
like git version, paths, etc. This commit fix that catching the ES exception instead of letting it 
escape to the method response.

index/src/main/java/org/fao/geonet/index/es/EsRestClient.java

@@ -38,6 +38,7 @@
 import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;
 import org.apache.http.ssl.SSLContextBuilder;
 import org.apache.lucene.search.TotalHits;
+import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ElasticsearchStatusException;
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -504,7 +505,7 @@ public String getServerStatus() throws IOException {
 //        return getClient().ping(RequestOptions.DEFAULT);
     }
 
-    public String getServerVersion() throws IOException {
+    public String getServerVersion() throws IOException, ElasticsearchException {
         MainResponse.Version version = client.info(RequestOptions.DEFAULT).getVersion();
 
         return version.getNumber();

services/src/main/java/org/fao/geonet/api/site/SiteInformation.java

@@ -28,6 +28,7 @@
 import jeeves.server.context.ServiceContext;
 import org.apache.commons.dbcp2.BasicDataSource;
 import org.apache.commons.lang.StringUtils;
+import org.elasticsearch.ElasticsearchException;
 import org.fao.geonet.GeonetContext;
 import org.fao.geonet.constants.Geonet;
 import org.fao.geonet.kernel.search.EsSearchManager;
@@ -65,7 +66,7 @@ public SiteInformation(final ServiceContext context, final GeonetContext gc) {
             }
             try {
                 loadIndexInfo(context);
-            } catch (IOException e) {
+            } catch (IOException | ElasticsearchException e) {
                 Log.error(Geonet.GEONETWORK, e.getMessage(), e);
             }
             loadEnvInfo();