docs(java): android: improve permission guide

templates/java/libraries/okhttp-gson/README.mustache

@@ -152,7 +152,7 @@ To upload a video, you have 3 differents methods:
 
 ## Permissions
 
-You have to add the following permissions in your `AndroidManifest.xml`:
+If your video files are located in the media store, you have to add the following permissions in your `AndroidManifest.xml`:
 
 ```xml
     <uses-permission android:name="android.permission.INTERNET" />
@@ -166,6 +166,8 @@ You have to add the following permissions in your `AndroidManifest.xml`:
 
 Your application also has to dynamically request the `android.permission.READ_EXTERNAL_STORAGE` permission to upload videos.
 
+If your video files are located in the app-specific storage, you don't need to request any permissions nor add any permissions to your `AndroidManifest.xml`.
+
 ### WorkManager
 
 To upload with the `WorkManager`, you also have to add the following lines in your `AndroidManifest.xml`: