d3d11screencapturesrc: Fix build error with MSVC x86

Delete the code for now. Note that the code block is unnecessary already

Background

    gst-plugins-bad: Fix build error on MSVC x86
    
    ```
    FAILED: sys/d3d11/gstd3d11.dll.p/gstd3d11winrtcapture.cpp.obj
    ../sys/d3d11/gstd3d11winrtcapture.cpp(446): error C2672: 'Callback': no matching overloaded function found
    ../sys/d3d11/gstd3d11winrtcapture.cpp(447): error C2784: 'Microsoft::WRL::ComPtr<Details::DelegateArgTraitsHelper<TDelegateInterface,false>::Interface> Microsoft::WRL::Callback(TCallbackObject *,HRESULT (__thiscall TCallbackObject::* )(TA
    rgs...)) throw()': could not deduce template argument for 'HRESULT (__thiscall TCallbackObject::* )(TArgs...)' from 'HRESULT (__stdcall GstD3D11WinRTCaptureInner::* )(ABI::Windows::Graphics::Capture::IGraphicsCaptureItem *,IInspectable *)
    '
    C:\Program Files (x86)\Windows Kits\10\include\10.0.20348.0\winrt\wrl\event.h(477): note: see declaration of 'Microsoft::WRL::Callback'
    ../sys/d3d11/gstd3d11winrtcapture.cpp(447): error C2780: 'Microsoft::WRL::ComPtr<Details::DelegateArgTraitsHelper<TDelegateInterface,false>::Interface> Microsoft::WRL::Callback(TFunc *) throw()': expects 1 arguments - 2 provided
    C:\Program Files (x86)\Windows Kits\10\include\10.0.20348.0\winrt\wrl\event.h(465): note: see declaration of 'Microsoft::WRL::Callback'
    ../sys/d3d11/gstd3d11winrtcapture.cpp(447): error C2780: 'Microsoft::WRL::ComPtr<Details::DelegateArgTraitsHelper<TDelegateInterface,false>::Interface> Microsoft::WRL::Callback(TLambda &&) throw()': expects 1 arguments - 2 provided
    C:\Program Files (x86)\Windows Kits\10\include\10.0.20348.0\winrt\wrl\event.h(457): note: see declaration of 'Microsoft::WRL::Callback'
    ../sys/d3d11/gstd3d11winrtcapture.cpp(448): error C3536: 'closed_handler': cannot be used before it is initialized
    ```
    
    Part-of: <https://gitlab.freedesktop.org/gstreamer/cerbero/-/merge_requests/1006>