agm-data-layer [style] is falling back to default styles on any change in the geojson

[wajeehmisbahkhan]

Issue description
This may be part of a bigger problem but when my data layer changes depending on the Firestore stream, the fill color became light black and the strokes become black and become thicker which I assume are all the default styles.

Steps to reproduce and a minimal demo of the problem
I've reproduced it based on setInterval instead of a live stream of data:
https://stackblitz.com/edit/angular-google-maps-demo-ubxsif?file=app/app.component.ts
The invertColor works fine in the constructor outside of the setInterval but after the map has loaded, it no longer works.

Current behavior
It changes the styles to the default settings.

Expected/desired behavior
It should change the style to the new GeoJson.

angular-google-maps, Angular, & any other relevant dependency versions
Mentioned in the package.json

Note - This was originally posted here:
sebholstein/angular-google-maps#1930

Reposting here as this seems to be a more active fork.