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/nibble/boards/nice_nano.overlay

@@ -25,7 +25,6 @@
 
     led_strip: ws2812@0 {
         compatible = "worldsemi,ws2812-spi";
-        label = "WS2812";
 
         /* SPI */
         reg = <0>; /* ignored, but necessary for SPI bindings */

app/boards/shields/nibble/boards/nice_nano_v2.overlay

@@ -25,7 +25,6 @@
 
     led_strip: ws2812@0 {
         compatible = "worldsemi,ws2812-spi";
-        label = "WS2812";
 
         /* SPI */
         reg = <0>; /* ignored, but necessary for SPI bindings */

app/boards/shields/nibble/nibble.overlay

@@ -15,7 +15,6 @@
 
     encoder_1: encoder_1 {
         compatible = "alps,ec11";
-        label = "Encoder 1";
         a-gpios = <&pro_micro 9 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
         b-gpios = <&pro_micro 8 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
         steps = <80>;
@@ -24,7 +23,6 @@
 
     kscan0: kscan {
         compatible = "zmk,kscan-gpio-demux";
-        label = "KSCAN";
         polling-interval-msec = <25>;
         input-gpios
             = <&pro_micro 15 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>
@@ -62,7 +60,6 @@ RC(4,0) RC(4,1) RC(4,2) RC(4,3)                 RC(4,6)                 RC(4,9)
     oled: ssd1306@3c {
         compatible = "solomon,ssd1306fb";
         reg = <0x3c>;
-        label = "DISPLAY";
         width = <128>;
         height = <32>;
         segment-offset = <0>;