Revert "Set cell_number to 0 if history is not available"

This reverts commit 4f6201b.

Author: nicolaskruchten

Diff for: packages/python/plotly/plotly/io/_base_renderers.py

@@ -609,14 +609,11 @@ def to_mimebundle(self, fig_dict):
 
     def build_filename(self):
         ip = IPython.get_ipython() if IPython else None
-        if ip:
-            cell_number = next(ip.history_manager.get_tail(1), (0, -1, ""))[1] + 1
-        else:
-            cell_number = 0
-
-        return "{dirname}/figure_{cell_number}.html".format(
+        cell_number = list(ip.history_manager.get_tail(1))[0][1] + 1 if ip else 0
+        filename = "{dirname}/figure_{cell_number}.html".format(
             dirname=self.html_directory, cell_number=cell_number
         )
+        return filename
 
     def build_url(self, filename):
         return filename