Question: In iOS 12.2, apple added a new “feature” where motion and orientation access in safari is disabled by default. Is there a way to use JavaScript to access this option (or trigger a system pop-up that the user can say yes or no to that will enable access) so the user doesn’t have to manually enable it?

Answer: 
Not yet.

"The only solution right now is to show a message to user to go to Settings and enable feature before some of the events are started (such as deviceorientation).

There is an API coming to request permission per site, but the WebKit team didn’t have time to get it done for this release. Chris Dumez from Apple confirmed that."

<https://medium.com/@firt/whats-new-on-ios-12-2-for-progressive-web-apps-75c348f8e945>
theres no official way yet, but you can probably do something like this (user will still have to manually enable it but at least you can tell them whats going on):

<https://github.com/w3c/deviceorientation/issues/57>