JupyterViz grid display should be optional, since not all models use a grid or agent space #1778
Description
What's the problem this feature will solve?
currently JupyterViz breaks if model.grid is not defined
Describe the solution you'd like
model.grid should continue to be optional; space should only be drawn when the model has a grid.
From testing locally, it looks like it is sufficient to modify the make_space method to check for the grid attribute and do nothing when it is defined. I'm willing to open a PR with this change if this solution is sufficient.
Additional context
Some discussion on #1772