[Feature][MYSQL-CDC] Support canal-json format

### Search before asking

- [x] I had searched in the [feature](https://github.com/apache/seatunnel/issues?q=is%3Aissue+label%3A%22Feature%22) and found no similar feature requirement.

### Description

We have a business requirement to output MySQL CDC data into a RocketMQ sink. However, we’ve noticed that most CDC sources do not support the Canal-JSON format, and only Debezium is supported. Due to business constraints, we cannot switch to Debezium.

Additionally, we’ve observed that updates are split into a DELETE and an INSERT, which complicates downstream processing.

Could you please explain:
1. Why most CDC sources do not support Canal-JSON format?
2. Are there any existing fixes or plans to add support for Canal-JSON in the future?

### Expected
```json
{
"data": [
{
"id": "111",
"name": "scooter",
"description": "Big 2-wheel scooter",
"weight": "5.18"
}
],
"database": "inventory",
"es": 1589373560000,
"id": 9,
"isDdl": false,
"mysqlType": {
"id": "INTEGER",
"name": "VARCHAR(255)",
"description": "VARCHAR(512)",
"weight": "FLOAT"
},
"old": [
{
"weight": "5.15"
}
],
"pkNames": [
"id"
],
"sql": "",
"sqlType": {
"id": 4,
"name": 12,
"description": 12,
"weight": 7
},
"table": "products",
"ts": 1589373560798,
"type": "UPDATE"
}
```
### Actually
```json
{
"data": [{
"id": 2348,
"user_id": "user_742852",
"user_name": "刘晶",
"email": "lisaanderson@example.org",
"age": 63,
"amount": 402.45,
"random_number": 109008,
"status": "inactive",
"created_at": "2025-08-25T01:56:17",
"updated_at": "2025-08-25T01:56:17"
}],
"type": "INSERT"
}
```

### Usage Scenario

_No response_

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

No source files, tests, or entry points are identified in the issue. Start by locating the MySQL CDC serialization path and existing Debezium handling, then compare its output with the requested Canal-JSON structure; done means UPDATE events preserve the expected Canal-JSON fields and no longer appear only as separate DELETE and INSERT records.

Written by the indexing model from the issue text.