How to Re-enable Disabled 'Files' App on Sony Xperia XZ3?

I accidentally disabled 'files' app in my device (Sony Xperia XZ3) and now I can not find any option for enabling it. The app is shown in my settings but labelled as disabled. And I cannot even find the same app on Play store. How can I enable files app? I already tried reset app option but it doesn't work.