Update googlemaps fitbounds method to include padding (#23071)

fitbounds has an optional second argument: padding.

reference: https://developers.google.com/maps/documentation/javascript/reference (see Methods section, first method).

types/googlemaps/index.d.ts

@@ -31,7 +31,7 @@ declare namespace google.maps {
     /***** Map *****/
     export class Map extends MVCObject {
         constructor(mapDiv: Element|null, opts?: MapOptions);
-        fitBounds(bounds: LatLngBounds|LatLngBoundsLiteral): void;
+        fitBounds(bounds: LatLngBounds|LatLngBoundsLiteral, padding?: number): void;
         getBounds(): LatLngBounds|null|undefined;
         getCenter(): LatLng;
         getDiv(): Element;