[BUG] AccessDeniedException: Processing files in removable storage on Android 9 & earlier

[deltazefiro]

Describe the bug / 问题描述 Processing files in removable storage results in an AccessDeniedException on devices running Android 9 & earlier.
It looks like the hider just "skipped" those folders.

Basic Information (please complete the following information) / 请填写以下信息:

• OS (ROM) / 系统: -
• Android Version / 安卓版本: 8, 8.1, 9
• Amarok Version / Amarok版本: current HEAD