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/bat43/bat43.overlay

@@ -28,7 +28,6 @@ RC(2,0) RC(2,1) RC(2,2) RC(2,3) RC(2,4) RC(2,5)         RC(6,0) RC(6,1) RC(6,2)
 
     kscan0: kscan_0 {
         compatible = "zmk,kscan-gpio-matrix";
-        label = "KSCAN";
         diode-direction = "col2row";
 
         col-gpios