fix(node): fix unexpected extra equals sign in HTTP params (#23474)

api/core/workflow/nodes/http_request/executor.py

         self.auth = node_data.authorization
         self.timeout = timeout
         self.ssl_verify = node_data.ssl_verify
-        self.params = []
+        self.params = None
         self.headers = {}
         self.content = None
         self.files = None
                 (self.variable_pool.convert_template(key).text, self.variable_pool.convert_template(value_str).text)
             )
 
-        self.params = result
+        if result:
+            self.params = result
 
     def _init_headers(self):
         """

api/tests/unit_tests/core/workflow/nodes/http_request/test_http_request_executor.py

     assert executor.method == "post"
     assert executor.url == "https://api.example.com/data"
     assert executor.headers == {"Content-Type": "application/json"}
-    assert executor.params == []
+    assert executor.params is None
     assert executor.json == {"number": 42}
     assert executor.data is None
     assert executor.files is None
     assert executor.method == "post"
     assert executor.url == "https://api.example.com/data"
     assert executor.headers == {"Content-Type": "application/json"}
-    assert executor.params == []
+    assert executor.params is None
     assert executor.json == {"name": "John Doe", "age": 30, "email": "john@example.com"}
     assert executor.data is None
     assert executor.files is None
     assert executor.method == "post"
     assert executor.url == "https://api.example.com/data"
     assert executor.headers == {"Content-Type": "application/json"}
-    assert executor.params == []
+    assert executor.params is None
     assert executor.json == {"object": {"name": "John Doe", "age": 30, "email": "john@example.com"}}
     assert executor.data is None
     assert executor.files is None
     assert executor.url == "https://api.example.com/upload"
     assert "Content-Type" in executor.headers
     assert "multipart/form-data" in executor.headers["Content-Type"]
-    assert executor.params == []
+    assert executor.params is None
     assert executor.json is None
     # '__multipart_placeholder__' is expected when no file inputs exist,
     # to ensure the request is treated as multipart/form-data by the backend.