shot: Get only cropped region from WindowServer

Previously, we were always getting the full screen(s) bitmap from
the WindowServer and cropping it manually. The `get_screen_bitmap`
function already took in a `crop_region`, so we are now utilizing
that.

Userland/Utilities/shot.cpp

@@ -131,7 +131,7 @@ int main(int argc, char** argv)
     if (screen >= 0)
         screen_index = (u32)screen;
     dbgln("getting screenshot...");
-    auto shared_bitmap = GUI::WindowServerConnection::the().get_screen_bitmap({}, screen_index);
+    auto shared_bitmap = GUI::WindowServerConnection::the().get_screen_bitmap(crop_region, screen_index);
     dbgln("got screenshot");
 
     RefPtr<Gfx::Bitmap> bitmap = shared_bitmap.bitmap();
@@ -140,10 +140,6 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    if (select_region) {
-        bitmap = bitmap->cropped(crop_region);
-    }
-
     if (output_to_clipboard) {
         GUI::Clipboard::the().set_bitmap(*bitmap);
         return 0;