Fix Win32Thread not capturing by move

std::function does not allow non-movable lambdas, so capturing by move
doesn't work there. And the old solution of course has issues with
dangling pointers (but because this is C++ the compiler still thinks
it's A-Ok).

src/wine-host/utils.cpp

@@ -18,7 +18,8 @@
 
 PluginContext::PluginContext() : context(), events_timer(context) {}
 
-uint32_t WINAPI win32_thread_trampoline(std::function<void()>* entry_point) {
+uint32_t WINAPI
+win32_thread_trampoline(fu2::unique_function<void()>* entry_point) {
     (*entry_point)();
     delete entry_point;