fix UriComponentsBuilder in PromqlQueryExecutor

hertzbeat-warehouse/src/main/java/org/apache/hertzbeat/warehouse/db/PromqlQueryExecutor.java

diff --git a/hertzbeat-warehouse/src/main/java/org/apache/hertzbeat/warehouse/db/PromqlQueryExecutor.java b/hertzbeat-warehouse/src/main/java/org/apache/hertzbeat/warehouse/db/PromqlQueryExecutor.java
index 6c7ea46..ee51990 100644
--- a/hertzbeat-warehouse/src/main/java/org/apache/hertzbeat/warehouse/db/PromqlQueryExecutor.java
+++ b/hertzbeat-warehouse/src/main/java/org/apache/hertzbeat/warehouse/db/PromqlQueryExecutor.java
@@ -41,7 +41,6 @@
 import org.springframework.web.util.UriComponentsBuilder;
 
 import java.net.URI;
-import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.LinkedList;