[Feature] support an option to force expiration.

### Search before asking

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

### Motivation

Sort compact only supports write-only mode, during which expiration operations are not performed. When users write data in write-only mode and use sort compact for sorting and merging, expired deletion cannot be executed.

### Solution

Add an option to force expiration.

### Anything else?

_No response_

### Are you willing to submit a PR?

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

Start by tracing sort compact and its write-only mode, then locate how expiration operations are currently triggered. Define where the new force-expiration option belongs and verify that enabling it performs expired deletion during sorting and merging in write-only mode.

Written by the indexing model from the issue text.