[fix][dingo-sdk] Added key-based document service retrieval

Author: githubgxll

java/dingo-sdk/src/main/java/io/dingodb/sdk/service/Services.java

@@ -305,6 +305,16 @@ public static IndexService indexRegionService(
         ).getService();
     }
 
+    @SneakyThrows
+    public static DocumentService documentRegionService(
+            Set<Location> locations, byte[] key, int retry
+    ) {
+        return new ServiceCaller<>(
+                regionChannelProvider(locations, key), retry, DEFAULT, DocumentService.Impl::new
+        ).getService();
+    }
+
+
     @SneakyThrows
     public static StoreService storeRegionService(
         Set<Location> locations, long regionId, int retry