[Umbrella] Subissue Improve table.* test coverage

### Search before asking

- [x] I searched in the [issues](https://github.com/alibaba/fluss/issues) and found nothing similar.

### Description

Currently, we ignore a lot of classes to make the code coverage pass. We need to add unit tests or integration tests around those classes to improve the coverage.
In this issue, it aims to cover `com.alibaba.fluss.table.*` to increase the coverage.

### Willingness to contribute

- [ ] I'm willing to submit a PR!

Start by reviewing the existing unit and integration tests alongside the classes in com.alibaba.fluss.table.* that are currently excluded from coverage. Done means adding tests for the relevant classes and confirming that table-package coverage improves without relying on coverage exclusions.

Written by the indexing model from the issue text.