/system/etc/permissions/com.google.android.camera.experimental2017.xml
/system/etc/permissions/com.google.android.camera.experimental2016.xml
/system/framework/com.google.android.camera.experimental2016.jar
/system/framework/com.google.android.camera.experimental2017.jar
In some cases, you also need to redo an updated GApps package after removing the files. Keep in mind that intermittent and dirty GApps can cause some problems if the GApps you already installed are old. A nandroid backup (TWRP) or a clean install is recommended.