[Fix][Connectors-v2] Fix UT for connector-http (#9821)

Author: hawk9821

seatunnel-connectors-v2/connector-http/connector-http-base/src/test/java/org/apache/seatunnel/connectors/seatunnel/http/HttpSourceReaderInternalPollNextTest.java

@@ -121,8 +121,9 @@ public void testPageNumberPlaceHolderRequestBodyUpdate() throws Exception {
         httpSourceReader =
                 new HttpSourceReader(
                         httpParameter, context, deserializationSchema, jsonField, null, pageInfo);
+        // This creates a real HTTP client. For testing purposes, we need to replace it with a mock.
         httpSourceReader.open();
-
+        httpSourceReader.setHttpClient(httpClientProvider);
         httpSourceReader.internalPollNext(collector);
 
         // Verify the body was updated correctly