[BUG] Tooltip not showing on the stroke of non-filled polygons

## Context

Tooltip not showing when hovering over.

## Resulting behavior, error message or logs

No tooltip is appearing for `PolygonLayer`:

But it does for `ScatterplotLayer`:

## Environment

- OS: macOS Sequoia
- Browser: VSCode notebook
- Lonboard Version: 0.14.0

## Steps to reproduce the bug

```python
import geopandas as gpd
import lonboard
import shapely as shp

lonboard.Map(
layers=lonboard.PolygonLayer.from_geopandas(
gdf=gpd.GeoDataFrame(
data={"name": ["BBOX"]},
geometry=[
shp.Polygon.from_bounds(
xmin=-77.14385447296375,
ymin=38.81777352822358,
xmax=-76.91327614087643,
ymax=38.997931216647345,
)
],
crs="4326",
),
filled=False,
line_width_units="pixels",
),
basemap=lonboard.basemap.MaplibreBasemap(style=lonboard.basemap.CartoStyle.Voyager),
show_tooltip=True,
)

lonboard.Map(
layers=lonboard.ScatterplotLayer.from_geopandas(
gdf=gpd.GeoDataFrame(
data={"name": ["Radius"]},
geometry=gpd.GeoSeries.from_xy(
x=[-77.04561819829546],
y=[38.9079099896949],
crs="4326",
),
),
filled=False,
get_radius=10_000,
line_width_units="pixels",
stroked=True,
),
basemap=lonboard.basemap.MaplibreBasemap(style=lonboard.basemap.CartoStyle.Voyager),
show_tooltip=True,
view_state={"zoom": 10, "latitude": 38.9079099896949, "longitude": -77.04561819829546},
)
```

Start by running the provided VSCode notebook reproduction with PolygonLayer and compare its tooltip behavior with the working ScatterplotLayer example. Trace the PolygonLayer behavior for non-filled polygons and verify that hovering the stroke shows the tooltip while preserving the existing filled-polygon behavior.

Written by the indexing model from the issue text.