enable get connection num in odp mode

Author: JackShi148

src/main/java/com/alipay/oceanbase/rpc/location/model/TableRoute.java

@@ -152,6 +152,9 @@ public long getLastRefreshMetadataTimestamp() {
 
     @VisibleForTesting
     public ObTable getFirstObTable() {
+        if (tableClient.isOdpMode()) {
+            return odpInfo.getObTable();
+        }
         return tableRoster.getTables().entrySet().iterator().next().getValue();
     }