V2.0.0 breaks formatting for lambda

[dephiros]

We tried to update the library to 2.0.0 but run into an issue where event sent from lambda no longer get formatted correctly.

Previously we use SentryJSONProcessor which is updated to SentryProcessor
We configure Sentry per the doc here: https://github.com/kiwicom/structlog-sentry?tab=readme-ov-file#logging-as-json

Example of previous message as seen on sentry:

Message
process_scheduled_message.message_not_handled

After the update the message becomes

Message
{'event': 'process_scheduled_message.message_not_handled', 'dd.trace_id': '4813741850791478619', 'dd.span_id': '13971470814306166836', 'dd.env': 'production'}

Somehow the JSON now is interpreted as a string.

Appreciate your help