[wpigui] Hardcode window scale to 1 on macOS (#3135)

This fixes an issue with scaling on Retina displays where the frame
buffer size was double that of the window size, resulting in a content
scale factor of 2. This scale factor caused elements to appear too
large, even on the smallest zoom setting.

This change does not affect external monitors on macOS because the
reported content scale was 1 anyway.

wpigui/src/main/native/cpp/wpigui.cpp

@@ -193,9 +193,11 @@ bool gui::Initialize(const char* title, int width, int height) {
   }
 
   if (!gContext->loadedWidthHeight) {
+#ifndef __APPLE__
     if (windowScale == 1.0) {
       glfwGetWindowContentScale(gContext->window, &windowScale, nullptr);
     }
+#endif
     // force user scale if window scale is smaller
     if (windowScale <= 0.5) {
       gContext->userScale = 0;
@@ -284,7 +286,9 @@ void gui::CommonRenderFrame() {
 
   // Scale based on OS window content scaling
   float windowScale = 1.0;
+#ifndef __APPLE__
   glfwGetWindowContentScale(gContext->window, &windowScale, nullptr);
+#endif
   // map to closest font size: 0 = 0.5x, 1 = 0.75x, 2 = 1.0x, 3 = 1.25x,
   // 4 = 1.5x, 5 = 1.75x, 6 = 2x
   gContext->fontScale = std::clamp(