"fluss-client" artifact shouldn't bundle dependencies

### Search before asking

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

### Description

Currently, `fluss-client` is a uber jar that bundles all the dependencies which is very heavy (around 64MB). It is designed not to be a uber jar. And flink connector jar should bundle the dependencies.

### Willingness to contribute

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

Start by locating the build configuration that produces the fluss-client artifact and the configuration for the Flink connector jar. Confirm how dependencies are currently bundled, then verify that fluss-client is no longer an uber jar while the Flink connector still bundles its required dependencies.

Written by the indexing model from the issue text.