fix(catalog): add validation for catalog_name parameter

csst_dfs_client/catalog.py

@@ -38,6 +38,8 @@ def search(ra: float,
 
     try:
         import pandas as pd
+        if not catalog_name:
+            return Result.error("catalog_name is required")
         datas = request.post('/api/catalog', {
                 'ra': ra,
                 'dec': dec,
@@ -93,6 +95,8 @@ def describe_catalog(catalog_name: str) -> Result:
     """
     try:
         import pandas as pd
+        if not catalog_name:
+            return Result.error("catalog_name is required")
         datas = request.get(f'/api/catalog/describe/{catalog_name}')
         if datas and isinstance(datas, Result):
             return datas