Default context value

[EkaterinaBurenina]

Describe the bug

The default value and the normal context value are different types

Steps to reproduce the behavior

1. setup_log_record()
2. logger.info("some text")
3. current_context[key] = value
4. logger.info("some text")

Expected vs actual behavior

I expect

"message": "some text", "context":   {}
"message": "some text", "context":  {key: value}

actual behavior

"message": "some text", "context":   ""
"message": "some text", "context":  {key: value}