[sysid] Remove unused dependency on libglassnt (#7200)

Also remove stale libuv references.

sysid/src/main/native/cpp/App.cpp

@@ -19,7 +19,6 @@
 #include <glass/WindowManager.h>
 #include <glass/other/Log.h>
 #include <imgui.h>
-#include <uv.h>
 #include <wpi/Logger.h>
 #include <wpi/print.h>
 #include <wpigui.h>
@@ -96,8 +95,6 @@ void Application(std::string_view saveDir) {
   });
 
   gLogger.set_min_level(wpi::WPI_LOG_DEBUG);
-  // Set the number of workers for the libuv threadpool.
-  uv_os_setenv("UV_THREADPOOL_SIZE", "6");
 
   // Initialize window manager and add views.
   auto& storage = glass::GetStorageRoot().GetChild("SysId");