When writing extremely long data to the DMdatabase, an error occurred: string truncation.

### 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

超长字符串写入达梦数据库，达梦报错：字符串截断，是因为达梦数据库插入字段默认有长度限制的。针对超长字符串，需将其转换为流后再传输，方可完成保存操作；同时也具备了对超长 JSON、大文本数据的处理能力

### 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 file, connector entry point, reproduction steps, or test is named in the issue. Start by reproducing the string-truncation error when writing very long strings to the Dameng database, then verify that long strings, JSON, and large text are saved successfully through stream-based handling.

Written by the indexing model from the issue text.