Python SDK: expose delete_segments

[justinmclean]

The Rust client has SegmentClient::delete_segments (core/common/src/traits/segment_client.rs), but the Python SDK has no binding for it. It is listed as Easy in the Python API alignment tracking issue, #3893.

What to do

• Add delete_segments(stream_id, topic_id, partition_id, segments_count) to foreign/python/src/client.rs. delete_partitions in the same file is the model to copy: it takes the same stream, topic and partition arguments, and this adds one u32 count.
• Regenerate foreign/python/apache_iggy.pyi by running cargo run --bin stub_gen from foreign/python, and commit the result. CI fails if the stub is out of date.
• Add foreign/python/tests/test_segment.py, following the setup and teardown in test_partition.py.

Done when

await client.delete_segments(stream_id, topic_id, partition_id, segments_count) returns None against a running server, and the new test passes.

Part of #3893.

[FenjuFu]

I'd like to work on this, could you assign it to me?

Plan: add delete_segments(stream_id, topic_id, partition_id, segments_count) to foreign/python/src/client.rs, modelled on delete_partitions. Unlike delete_partitions, it also takes partition_id, so there are two u32 arguments, matching SegmentClient::delete_segments. Then regenerate apache_iggy.pyi with cargo run --bin stub_gen, and add tests/test_segment.py following the setup and teardown in test_partition.py. I'll run the new test against a local server before opening the PR.

[hubcio]

@FenjuFu assigned, GL

[Hashim1999164]

I'd like to take this. I'll add delete_segments to the Python client following delete_partitions, regenerate the stub, and add a test.

[hubcio]

@Hashim1999164 this is already assigned to @FenjuFu.