I'm looking for the phone app for http://www.dji.com/flysafe/geo-system/map but can't seem to find this app in the google play store. What would the search to bring this up to do the install?

I don't think there's an App for that. It's a webpage you can access via your browser.

There is also an option when running DJI Go 4 App. On the main screen (where aircraft is selected) tap on the three bar icon at the top right of page. From there tap on the No-fly zone option and it will show you restrictions within your area (At least if you have wifi or data connection). These of course are based on DJI data.

Note:- Use two fingers to slide map across screen.