addTileOverlay does not render tiles on the iOS or android devices

**I'm submitting a ...** (check one with "x")
- [ ] question
- [X] any problem or bug report
- [ ] feature request

**If you choose 'problem or bug report', please select OS:** (check one with "x")
- [X] **Android**
- [X] **iOS**
- [ ] **Browser**

**cordova information:** (run `$> cordova plugin list`)

```
com.googlemaps.ios 3.9.0 "Google Maps SDK for iOS"
cordova-android-support-gradle-release 3.0.1 "cordova-android-support-gradle-release"
cordova-plugin-advanced-http 2.5.1 "Advanced HTTP plugin"
cordova-plugin-buildinfo 2.0.3 "BuildInfo"
cordova-plugin-camera 4.1.0 "Camera"
cordova-plugin-device 2.0.3 "Device"
cordova-plugin-facebook4 6.4.0 "Facebook Connect"
cordova-plugin-file 6.0.2 "File"
cordova-plugin-geolocation 4.0.2 "Geolocation"
cordova-plugin-globalization 1.11.0 "Globalization"
cordova-plugin-googlemaps 2.7.1 "cordova-plugin-googlemaps"
cordova-plugin-ionic 5.4.7 "cordova-plugin-ionic"
cordova-plugin-ionic-keyboard 2.2.0 "cordova-plugin-ionic-keyboard"
cordova-plugin-ionic-webview 4.2.1 "cordova-plugin-ionic-webview"
cordova-plugin-network-information 2.0.2 "Network Information"
cordova-plugin-sign-in-with-apple 0.1.2 "cordova-plugin-sign-in-with-apple"
cordova-plugin-splashscreen 5.0.4 "Splashscreen"
cordova-plugin-statusbar 2.4.3 "StatusBar"
cordova-plugin-telerik-imagepicker 2.3.5 "ImagePicker"
cordova-plugin-whitelist 1.3.4 "Whitelist"
cordova-sqlite-storage 3.4.1 "Cordova sqlite storage plugin - cordova-sqlite-storage plugin version"
cordova-universal-links-plugin 1.2.1 "Universal Links Plugin"

```

**If you use `@ionic-native/google-maps`, please tell the package.json (only `@ionic-native/core` and `@ionic-native/google-maps` are fine mostly)**

**Current behavior:**
On iOS or Android, if I add a tileOverlay, it does not render. Only the underlying google maps is shown. However, on cordova browser it works perfectly.

**Expected behavior:**
I see the tile overlay

**Related code, data or error log (please format your code or data):**

```
this.map = GoogleMaps.create('map_canvas', mapOptions);
this.map.addTileOverlaySync({
getTile: (x, y, z) => `https://tiles.stadiamaps.com/tiles/alidade_smooth/${z}/${x}/${y}@1x.png`
});
```