Flatpak version audio output device is inconsistent with the native system

[fanguohao]

描述 bug
flatpak 版本音频输出设备与本机设置不一致， 具体表现为：只能输出到line out 有线设备，蓝牙设备无法获得音频输出。

环境
ubuntu 22.04
goldendict 版本 24.09.13

复现 bug 的步骤

1. 打开软件
2. 连接蓝牙耳机 和有线设备，本机系统切换到蓝牙设备为输出
3. 点击任意单词发音，蓝牙设备无音频输出，有线设备输出音频。（其他flatpak 软件不存在此问题，如spotify音频输出与本机保持一致）

推测
内部绑定了单一输出设备，没有进行动态判断。

[github-actions]

Bot detected the issue body's language is not English, translate it automatically.

Describe bug
The audio output device of the flatpak version is inconsistent with the local settings. The specific performance is as follows: it can only be output to line out wired devices, and Bluetooth devices cannot obtain audio output.

environment
ubuntu 22.04
goldendict version 24.09.13

Steps to reproduce bug

1. Open the software
2. Connect the Bluetooth headset and wired device, and the local system switches to the Bluetooth device as the output
3. Click on the pronunciation of any word. The Bluetooth device has no audio output, and the wired device outputs audio. (Other flatpak software does not have this problem, such as spotify audio output is consistent with the native machine)

speculation
A single output device is bound internally and no dynamic judgment is made.

[xiaoyifang]

1, 切换输出后。 退出gd-ng,重新打开，是否正常。
2, 更改下音频的播放引擎， （内）外置的是否正常。

[github-actions]

Bot detected the issue body's language is not English, translate it automatically.

1, after switching output. Exit gd-ng and reopen it to see if it is normal.
2. Change the audio playback engine and see if the (internal) and external one is normal.

[fanguohao]

感谢！在内部切换到Qt multimedia 音频恢复正常～

通过pulseauido 查看发现，选中ffmpeg， 音频输出设备不受系统接管

[github-actions]

Bot detected the issue body's language is not English, translate it automatically.

grateful! Switch to Qt multimedia internally and the audio returns to normal~

Through pulseauido, we found that if ffmpeg is selected, the audio output device is not taken over by the system.