bug(iceberg): `add_files` doesn't actually check duplicated files

[Erigara]

Apache Iceberg Rust version

Latest main branch.

Describe the bug

I've noticed that add_files with check_duplicate doesn't find duplicated files.

The problem is that in the implementation instead of listing all files already exist in the table all manifest files instead are returned.

I've added print here to verify.

Here is what was returned (i trimmed path to exclude irrelevant parts):

s3://../039fe264-9c78-4f14-9d93-473b1d39afa6/metadata/a7149190-3785-4780-b416-3a62dfe2bd4b-m0.avro
s3://../039fe264-9c78-4f14-9d93-473b1d39afa6/metadata/e2eb79eb-c884-43a2-9a47-c35cef8aaf6b-m0.avro
...

To Reproduce

Create simple table, try to add the same file multiple times.

Expected behavior

Duplicated files are detected.

Willingness to contribute

I'm willing to contribute to this issue.