Add serialization baseline for Channel (#47451)

test_resources/serialization_baseline/collections/channels/My HTTP channel_my_http_channel.yaml

+active: true
+created_at: '2024-08-30T13:26:36.366837Z'
+description: null
+details:
+  auth-method: none
+  url: http://example.com
+name: My HTTP channel
+type: channel/http
+serdes/meta:
+- id: My HTTP channel
+  label: my_http_channel
+  model: Channel