refactor(app): remove `_gatt_` infixes from BT DIS and BAS services

See: https://docs.zephyrproject.org/latest/releases/release-notes-2.4.html
PR: #467

app/Kconfig

@@ -48,8 +48,8 @@ config ZMK_BLE
 	select BT_SMP_SC_PAIR_ONLY
 	select BT_SMP_APP_PAIRING_ACCEPT
 	select BT_PERIPHERAL
-	select BT_GATT_DIS
-	select BT_GATT_BAS
+	select BT_DIS
+	select BT_BAS
 	select BT_SETTINGS
 	select SETTINGS
 

app/src/battery.c

@@ -38,7 +38,7 @@ static int zmk_battery_update(const struct device *battery) {
 
     LOG_DBG("Setting BAS GATT battery level to %d.", state_of_charge.val1);
 
-    rc = bt_gatt_bas_set_battery_level(state_of_charge.val1);
+    rc = bt_bas_set_battery_level(state_of_charge.val1);
 
     if (rc != 0) {
         LOG_WRN("Failed to set BAS GATT battery level (err %d)", rc);

app/src/display/widgets/battery_status.c

@@ -32,7 +32,7 @@ void battery_status_init() {
 
 void set_battery_symbol(lv_obj_t *label) {
     char text[2] = "  ";
-    uint8_t level = bt_gatt_bas_get_battery_level();
+    uint8_t level = bt_bas_get_battery_level();
 
 #if IS_ENABLED(CONFIG_USB)
     if (zmk_usb_is_powered()) {