UI thread crash in WPF when using RTC SDK

Title:
UI thread crash in WPF after multiple join/leave operations with specific camera

Environment:
Platform: WPF (.NET)
Device: PC with two cameras
SDK: [please fill in RTC SDK name and version]

Steps to Reproduce:
1. Use a device that has two cameras.
2. Start an audio/video call by calling JoinChannel, and specify one of the cameras explicitly.
3. Leave the channel.
4. Repeat step 2 and 3 multiple times (typically 7–8 times).

Actual Result:
- After several join/leave cycles, the WPF application crashes, and the UI thread stops responding.
- Exception details:
System.InvalidCastException
HResult=0x80004002
Message=Unable to cast object of type 'System.__ComObject' to type 'ITfThreadMgr'.

Expected Result:
The application should remain stable even after repeatedly joining and leaving the channel.

Notes:
- The issue only appears when a specific camera is selected.
- If both cameras are available but not explicitly specified, the problem is less frequent.
- Related code excerpt:

```csharp
public override int JoinChannel(string? token, string channelId, bool localVideo, bool localAudio)
{

this.channelId = channelId;
LogStateChange(prev, _state, "开始加入频道");

try
{

// Accessing the video device manager and enumerating video devices here
// causes UI thread issues when called in WPF after multiple join/leave cycles.

var manager = rtc_engine_.GetVideoDeviceManager();
var list = manager.EnumerateVideoDevices();

if (list.Length > 1)
{
var temp = list[1];
var result = manager.SetDevice(temp.deviceId);
}

rtc_engine_.EnableVideo();
rtc_engine_.EnableAudio();
rtc_engine_.EnableLocalVideo(localVideo);
rtc_engine_.EnableLocalAudio(localAudio);

rtc_engine_.StartPreview(VIDEO_SOURCE_TYPE.VIDEO_SOURCE_CAMERA_PRIMARY);

ChannelMediaOptions options = new ChannelMediaOptions();
options.publishCameraTrack.SetValue(localVideo);
options.publishMicrophoneTrack.SetValue(localAudio);
options.channelProfile.SetValue(CHANNEL_PROFILE_TYPE.CHANNEL_PROFILE_LIVE_BROADCASTING);
options.clientRoleType.SetValue(CLIENT_ROLE_TYPE.CLIENT_ROLE_BROADCASTER);

var realChannel = (channelId.Split(';').GetValue(0) ?? string.Empty).ToString();
var ret = rtc_engine_.JoinChannel(token, realChannel, 0, options);
this.LogInfo($"JoinChannel Agora 调用 ret={ret}, realChannel={realChannel}");

if (ret != 0)
{
_state = EngineState.Initialized;
return ret;
}

rtc_engine_.EnableAudioVolumeIndication(300, 3, false);
return ret;
}
catch (Exception ex)
{
_state = EngineState.Initialized;
return -1;
}
}