There are a few UserVoice items marked as noted for the feature you're mentioning. Currently, the only option is to create an app configuration policy and apply it to the managed device or managed app. This is only available to Android work profile apps and apps that support the Intune App SDK.
I think users have been waiting for content locker on Intune for about 3 years. All the uservoices are referred back to the original request, but no news on progress or even if it’s on the roadmap. Competitor application like Airwatch have this it’s a real gap in the Intune application at present.