[Bug] spark connector, when doris table is non-paritioned. where clause is useless

### 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

1.2.9

### What's Wrong?

doris表是非分区表的情况下，用spark connector去读取到df以后。无法使用where 算子。写了也不生效，变成了全部读取，然后全表写入。


### What You Expected?

组件bug。

### How to Reproduce?

1.准备一个非分区的doris表。
2.插入100条数据
3.使用spark doris connector读取到df
4.随便加一个where算子，带上条件
最后会发现条件没用

### Anything Else?

_No response_

### Are you willing to submit PR?

- [x] 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)

Reproduce with Doris 1.2.9 using a non-partitioned table containing 100 rows, read it through the Spark connector, and apply a where condition. Trace the connector's read and predicate-handling path; done means the condition is honored so only matching rows are read rather than the entire table.

Written by the indexing model from the issue text.