[Bug][Jupyter Widget]

**Describe the bug**

Heatmap option for points does not show up after zooming from a certain point.

**To Reproduce**

Data:
I am Grid points that a are 1 meter far from each other with CRS 4326
points have different values that I am using as the weighting of the heatmap.

Data is pandas format containing the lat and lon columns. There is also a column with a time stamp for filtering and animation.

Steps to reproduce the behavior:
Code for generating Kepler HTML:
```
from keplergl import KeplerGl
map= KeplerGl(height=800, data={"data": pandas_df.to_csv()})
map
```
2. Configuring data visualization:
1. changing the visualization to the heatmap
2. adjusting the radius to have a suitable heatmap.
3. Weight Based On weight column.
4. filtering the day column to get the data

3. Zooming in causes the heatmap to disappear

**Screenshots**
before zoom

After zoom

**Environment (please complete the following information):**

- Python version: Python 3.8.5
- keplergl Widget version 0.2.1

**Additional context**
My data is located in Tampere, Finland

Thank you for all your time and efforts!