Runaway memory usage when working with msticpy

[jakebailey]

To reproduce:

1. Clone https://github.com/Microsoft/msticpy
2. Install dependencies in a venv (pip install -r requirements.txt)
3. Open msticpy\nbtools\__init__.py.

Memory is stable until a point (I think when analyzing plotly) when the memory usage just grows and grows.

[MikhailArkhipov]

Plotly is the root case.