[Feature] Support to stream read the chain table

### Search before asking

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

### Motivation

The chain table's delta partition should support the stream read

### Solution

_No response_

### Anything else?

_No response_

### Are you willing to submit a PR?

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

The issue identifies only the chain table's delta partition and its need for stream reads; it names no files, tests, or entry points. Start by locating the chain-table and stream-read implementations, then determine the expected behavior and tests needed to show that delta partitions can be read as a stream.

Written by the indexing model from the issue text.