fixing browser for lint

Author: BryanSchroeder

dash/testing/browser.py

@@ -160,9 +160,10 @@ def percy_snapshot(
         if widths is None:
             widths = [1280]
         try:
-            import asgiref  # pylint: disable=unused-import, # noqa: F401
-            name += '_async'
-        except:
+            import asgiref  # pylint: disable=unused-import, import-outside-toplevel # noqa: F401, C0415
+
+            name += "_async"
+        except ImportError:
             pass
 
         logger.info("taking snapshot name => %s", name)