Fix black screen issue

[SergeantSerk]

See my comment on #62. WGC was called from another marshalled thread. This seems to fix it.

However, there seems to be an issue with the audio capture that is similar to what had occurred with WGC. Keeping this as a draft until a fix for that can be identified too.

...
[libopus @ 0000019ab7abaac0] No bit rate set. Defaulting to 96000 bps.
[2025-03-15T17:50:41.420678000Z INFO mira_sharer::capture::audio] Begin recording audio
Exception thrown at 0x00007FFE3E02B699 (KernelBase.dll) in mira_sharer.exe: 0x8001010E: The application called an interface that was marshalled for a different thread.
Exception thrown at 0x00007FFE3E02B699 (KernelBase.dll) in mira_sharer.exe: WinRT originate error - 0x8001010E : 'The application called an interface that was marshalled for a different thread.'.
Exception thrown at 0x00007FFE3E02B699 in mira_sharer.exe: Microsoft C++ exception: winrt::hresult_wrong_thread at memory location 0x00000050B87F8620.
Exception thrown at 0x00007FFE3E02B699 in mira_sharer.exe: Microsoft C++ exception: [rethrow] at memory location 0x0000000000000000.
GraphicsCapture.dll!00007FFE205C6984: ReturnHr(1) tid(4b00) 8001010E The application called an interface that was marshalled for a different thread.
    Msg:[winrt::hresult_error: The application called an interface that was marshalled for a different thread.] 

thread 'tokio-runtime-worker' panicked at src\capture\wgc\wgc_capture.rs:40:45:
called `Result::unwrap()` on an `Err` value: Error { code: HRESULT(0x8001010E), message: "The application called an interface that was marshalled for a different thread." }
stack backtrace:
...