Remove appearance section in matrix_appservice_webhooks_configuration_yaml due to not being used

roles/matrix-bridge-appservice-webhooks/defaults/main.yml

@@ -66,11 +66,6 @@ matrix_appservice_webhooks_configuration_yaml: |
     # The localpart to use for the bot. May require re-registering the application service.
     localpart: "_webhook"
 
-    # Appearance options for the Matrix bot
-    appearance:
-      displayName: "Webhook Bridge"
-      avatarUrl: "http://i.imgur.com/IDOBtEJ.png" # webhook icon
-
   # Provisioning API options
   provisioning:
     # Your secret for the API. Required for all provisioning API requests.