Scheduled Event (V2) contains non-object detail parameter (it is a string)

When I'm using ScheduledEvent as a source event in the lambda handler where actually Amazon EventBridge Scheduler's Schedule is a trigger for the function, I'm getting
```
An error occurred during JSON parsing: java.lang.RuntimeException
java.lang.RuntimeException: An error occurred during JSON parsing
Caused by: java.io.UncheckedIOException: com.amazonaws.lambda.thirdparty.com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `java.util.LinkedHashMap` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('
{}
')
at [Source: (ByteArrayInputStream); line: 1, column: 318] (through reference chain: com.amazonaws.services.lambda.runtime.events.ScheduledEvent["detail"])
at com.amazonaws.services.lambda.runtime.serialization.factories.JacksonFactory$InternalSerializer.fromJson(JacksonFactory.java:199)
Caused by: com.amazonaws.lambda.thirdparty.com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `java.util.LinkedHashMap` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('
{}
')
```
because "detail" parameter in that event is not an object - it is a string. Look at this sample below from Java logger:
```
Event: {
"version": "0",
"id": "4e6638b7-b892-4482-9762-8c58d4e71ebb",
"detail-type": "Scheduled Event",
"source": "aws.scheduler",
"account": "xxx",
"time": "2024-05-06T10:58:00Z",
"region": "eu-west-1",
"resources": [
"arn:aws:scheduler:eu-west-1:xxx:schedule/default/xxx"
],
"detail": "{}"
}
```
IMO AWS should fix this event source for sending object-compatible field or we should implement new class e.g. `ScheduledV2Event` with a `String` type, not a Map. It looks like the "old" Scheduled Event is not compatible with the new Scheduled V2 Event.

まず ScheduledEvent モデルとスタックトレースで示されている JacksonFactory のデシリアライズ経路を確認し、次にそれらを示されている EventBridge Scheduler のペイロードと比較します。V2 scheduled event の文字列値の detail を、報告されている MismatchedInputException なしで表現およびデシリアライズでき、選択した互換性の動作がテストでカバーされていれば完了です。

索引モデルが issue の本文から書いたものです。