How to reproduce:
1. Open the attached project
2. You can delete Manifest from Android>Plugins and keep Click.cs and test scene
or
2. You can delete Click.cs and test scene and keep Manifest
3. In both ways it will use camera permissions, which are ephemeral
4. Build and run test scene on Android O device

Actual result: You won't get camera permissions pop up at the startup during clear install. Also one can see that in application settings camera permissions are disabled.
Expected result: It should either ask to allow using camera or grant permission automatically

Note:
Tested some more permissions:
-dangerous|ephemeral "android.permission.READ_PHONE_NUMBERS" works same as camera permissions
-dangerous "android.permission.BODY_SENSORS" pop up appears
-dangerous "android.permission.READ_EXTERNAL_STORAGE" pop up appears

DUT(reproducible):
90, Google Nexus 6p, 8.0.0
DUT(not reproducible):
137, Samsung Galaxy S8 [SM-G950F], 7.0.0