refactor: Remove unimportant labels

Removed "label" properties which no longer have any function.

Labels are still used as layer names and as identifiers for sending
behaviors between sides of a split keyboard, so those have been left
alone for now.

app/boards/shields/settings_reset/settings_reset.overlay

@@ -13,7 +13,6 @@
 
     kscan0: kscan {
         compatible = "zmk,kscan-mock";
-        label = "KSCAN";
         columns = <1>;
         rows = <0>;