geojson's opacity property not working

I am using Kepler.gl for a react project. I have datasets with polygons, which I want to be transparent. I am passing the opacity property in the geoJson

```
{
type: "Feature",
geometry: {
type: "Polygon",
coordinates: [
[
[12.57638102369686, 55.68100585730289],
[12.575605804451902, 55.68048395158776],
[12.576431037841035, 55.680034919024024],
[12.577447992118934, 55.68072844882596],
[12.57638102369686, 55.68100585730289]
]
]
},
properties: {
lineColor: [130, 154, 227],
lineWidth: 0.05,
opacity: 0.2,
fillColor: [0, 0, 256],
},
id: uuid()
},
```
which then gets processed by the kepler's geojson processor

```
const datasets = []
dataSource.features.map((feature, index) =>
datasets.push({
info: {
label: `${index}`,
id: `${index}`
},
data: processGeojson(feature)
})
)
useEffect(() => {
dispatch(
addDataToMap({
datasets: datasets,
options: {
centerMap: true,
readOnly: false
},
config: config
})
)
}, [dataSource])
```
The other properties work (lineColor, lineWidth, etc.) It's only the opacity that does not seem to do anything.

Start by tracing the feature through processGeojson and addDataToMap, then reproduce the polygon dataset with opacity set to 0.2. Inspect how the processed properties reach the map rendering path and verify that the polygon becomes visibly transparent while lineColor and lineWidth continue to work.

Written by the indexing model from the issue text.