[osx] Don't use obsoleted function on macOS 15.0 (fix aseprite/aseprite#4880)

If we target laf for macOS 15.0, we cannot use the obsoleted
CGDisplayCreateImageForRect() function. We have to re-implement the
getColorFromScreen() functionality through ScreenCaptureKit in a near
future.

Author: dacap

os/osx/system.mm

@@ -1,5 +1,5 @@
 // LAF OS Library
-// Copyright (c) 2020-2023  Igara Studio S.A.
+// Copyright (c) 2020-2025  Igara Studio S.A.
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -108,6 +108,12 @@
 gfx::Color SystemOSX::getColorFromScreen(const gfx::Point& screenPosition) const
 {
   gfx::Color color = gfx::ColorNone;
+
+#if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_15_0
+  // TODO Use ScreenCaptureKit for macOS 15.0 as
+  //      CGDisplayCreateImageForRect() function is obsoleted in
+  //      this version.
+#else
   CGImageRef image = CGDisplayCreateImageForRect(
     CGMainDisplayID(),
     CGRectMake(screenPosition.x, screenPosition.y, 1, 1));
@@ -135,6 +141,7 @@
     }
     CGImageRelease(image);
   }
+#endif
   return color;
 }