Add missing define check for LCD calls (#33180)

diff --git a/examples/lit-icd-app/silabs/src/AppTask.cpp b/examples/lit-icd-app/silabs/src/AppTask.cpp
index 0fb9826..0f330e7 100644
--- a/examples/lit-icd-app/silabs/src/AppTask.cpp
+++ b/examples/lit-icd-app/silabs/src/AppTask.cpp
@@ -170,11 +170,15 @@
 // DO NOT COPY for product logic. LIT ICD app is a test app with very simple application logic to enable testing.
 void AppTask::OnEnterActiveMode()
 {
+#ifdef DISPLAY_ENABLED
     sAppTask.GetLCD().WriteDemoUI(true);
+#endif
 }
 
 // DO NOT COPY for product logic. LIT ICD app is a test app with very simple application logic to enable testing.
 void AppTask::OnEnterIdleMode()
 {
+#ifdef DISPLAY_ENABLED
     sAppTask.GetLCD().WriteDemoUI(false);
+#endif
 }