feat(shields): Add ZMK Uno nice!view support.

Export the `nice_view_spi` node properly from the ZMK Uno overlay
to ensure the shield will work when built along with the `nice_view`
shield.

app/boards/shields/zmk_uno/zmk_uno.overlay

@@ -11,9 +11,15 @@
     status = "okay";
 };
 
-&arduino_spi {
+nice_view_spi: &arduino_spi {
     status = "okay";
 
+    cs-gpios = <&arduino_header 16 GPIO_ACTIVE_HIGH>;
+
+    // Needed so the nice_view shield will enhance the existing node which falls *first*
+    // on the bus, properly picking up the first `cs-gpios` specifier.
+    ls0xx@0 {};
+
     led_strip: ws2812@0 {
         compatible = "worldsemi,ws2812-spi";