Do not clean up resources after execution

Revert #969

This should never have been merged. The client still needs the kernel
and channels running after execution !

Co-authored-by: davidbrochart <davidbrochart@users.noreply.github.com>

voila/notebook_renderer.py

@@ -244,8 +244,6 @@ async def _jinja_notebook_execute(self, nb, kernel_id):
         #  (it seems to be local to our block)
         nb.cells = result.cells
 
-        await self._cleanup_resources()
-
     async def _jinja_cell_generator(self, nb, kernel_id):
         """Generator that will execute a single notebook cell at a time"""
         nb, _ = ClearOutputPreprocessor().preprocess(
@@ -295,12 +293,6 @@ async def _jinja_cell_generator(self, nb, kernel_id):
             finally:
                 yield output_cell
 
-        await self._cleanup_resources()
-
-    async def _cleanup_resources(self):
-        await ensure_async(self.executor.km.cleanup_resources())
-        await ensure_async(self.executor.kc.stop_channels())
-
     async def load_notebook(self, path):
         model = await ensure_async(self.contents_manager.get(path=path))
         if "content" not in model: