RGBCW lightbulb: change some types from hex to base64

sleep_mode, wake_mode, rhythm_mode seem to be base64 when they are sent, not hex.
Although they are unused, the code now decodes them under the hood, so mismatches are
reported as warnings.

custom_components/tuya_local/devices/rgbcw_lightbulb.yaml

@@ -79,15 +79,15 @@ primary_entity:
       optional: true
     - id: 30
       name: rhythm_mode
-      type: hex
+      type: base64
       optional: true
     - id: 31
       name: sleep_mode
-      type: hex
+      type: base64
       optional: true
     - id: 32
       name: wakeup_mode
-      type: hex
+      type: base64
       optional: true
 secondary_entities:
   - entity: number