[Bug] Doris作为source时，Flink-ui上算子显示buzy 100%

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/incubator-doris/issues?q=is%3Aissue) and found no similar issues.

### Version

org.apache.doris
flink-doris-connector-1.17
25.1.0

### What's Wrong?

Doris作为source时，Flink-ui上算子显示buzy 100%

### What You Expected?

这个是正常的么

### How to Reproduce?

_No response_

### Anything Else?

_No response_

### Are you willing to submit 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)

Start with the flink-doris-connector-1.17 dependency at version 25.1.0 and reproduce the Doris-as-source case shown in the Flink UI. Determine whether 100% operator busy status is expected or indicates a connector problem; the issue provides no reproduction steps, source file, or test to target.

Written by the indexing model from the issue text.