hssm.graph() does not render in marimo notebook

**Describe the bug**
hssm.graph() does not render in a marimo notebook.

**HSSM version**
Version: 0.2.11

**To Reproduce**
```
import marimo as mo
import hssm
import numpy as np

v_true = 0.5
a_true = 1.5
z_true = 0.5
t_true = 0.5

param_dict_init = dict(
v=v_true,
a=a_true,
z=z_true,
t=t_true,
)

dataset_simulated_main = hssm.simulate_data(
model="ddm",
theta=param_dict_init,
size=500,
)

simple_ddm_model = hssm.HSSM(data=dataset_simulated_main)
simple_ddm_model.graph()
```

**Screenshots**
Image within marimo environment with a convert to png solution.

**Additional context**
A similar problem was reported and fixed for pymc.Model: https://github.com/pymc-devs/pymc/pull/7830

Start with the provided hssm.HSSM.graph() reproduction in a marimo notebook and compare the related pymc.Model fix in PR 7830. Done means the graph renders in marimo without the convert-to-PNG workaround.

Written by the indexing model from the issue text.