Rename deprecated light rgb_order to channel_colors

ESPHome renamed the esp32_rmt_led_strip platform's rgb_order option to
channel_colors; update the remaining devices using it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

mcu-cec-bedroom.yaml

@@ -71,7 +71,7 @@ light:
   - platform: esp32_rmt_led_strip
     name: LED
     id: led
-    rgb_order: GRB
+    channel_colors: GRB
     pin: 27
     num_leds: 1
     chipset: ws2812