Event not JSON serializable - Recorder

[cdce8p]

Description:

Not all events JSON serializable. This mainly applies to service_call events for which templates aren't rendered yet. Since the template doesn't have knowledge of hass yet (at the moment of the service_call), it can't render itself either. See the issue linked below for an example.

Originally I though of rendering it after the serialization failed (a00bd34), but I think that would overly complicate things. That's why I would propose changing the warning message to a debug one.

A assume similar chases would apply from States.

Related issue (if applicable): fixes #18900

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

[balloob]

All events should be JSON serializable. If an event is not JSON serializable, it's a bug.

Service schemas should not use validators that produce data types that are not serializable. This is breaking a lot of other things too, like if we would want to send the event over the websocket connection or when using MQTT event stream.