Support general DELETE statement on primary key table

### Search before asking

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

### Motivation

See the discussion https://github.com/apache/fluss/pull/1201#discussion_r2168287356

Currently, we only support DELETE statement on primary key table with equal condition on primary key. This is very limited and we should support general DELETE statement like how we implement UPDATE statement via `org.apache.fluss.flink.sink.FlinkTableSink#applyRowLevelUpdate`.

### Solution

_No response_

### Anything else?

_No response_

### Willingness to contribute

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

Start by reading org.apache.fluss.flink.sink.FlinkTableSink#applyRowLevelUpdate and the linked discussion in pull request 1201, then trace the current DELETE handling for primary-key tables. Done means DELETE statements support conditions beyond equality on the primary key, consistently with the existing row-level update approach.

Written by the indexing model from the issue text.