samples: basic: button: Disable led on xgm240 boards

Button 0 and LED 0 share a GPIO pin on xgm240 boards. Remove the
`led0` alias in a board overlay to make the button sample work
out of the box.

Signed-off-by: Aksel Skauge Mellbye <aksel.mellbye@silabs.com>

Author: asmellby

samples/basic/button/boards/xgm240_rb4316a.overlay

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Silicon Laboratories Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		/* led0 interferes with sw0 since it uses the same pin */
+		/delete-property/ led0;
+	};
+};

samples/basic/button/boards/xgm240_rb4317a.overlay

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Silicon Laboratories Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		/* led0 interferes with sw0 since it uses the same pin */
+		/delete-property/ led0;
+	};
+};