fix: Fix the non-empty check of the tool input parameters

Author: hao65103940

apps/tools/serializers/tool.py

@@ -431,7 +431,7 @@ def get_field_value(debug_field_list, name, is_required):
 
         @staticmethod
         def convert_value(name: str, value: str, _type: str, is_required: bool):
-            if not is_required and value is None:
+            if not is_required and (value is None or (isinstance(value, str) and len(value.strip()) == 0)):
                 return None
             try:
                 if _type == 'int':