[@capacitor/google-maps] -> Feature -> map.getPolygons()

## Feature Request

### Plugin

@capacitor/google-maps

### Description

right now you can do `map.addPolygon()` and `map.removePolygon()` and thats all well and good. but i want to save my polygons and to do that I need the data. From what I can see, there is nothing in the API that allows me to do so.

### Platform(s)

iOS, Web, Android

### Preferred Solution

ideally the interface would look like below. the array of strings parameter in this case is 1 or more polygon id's. This seems consistent with how the other polygon methods work ( using string ids to remove ).
`map.getPolygons(polygons : string[])`

### Alternatives

### Additional Context