[BUG] SKIP_CREDENTIAL_SUBSCOPING_INDIRECTION is ignored in TaskFileIOSupplier

[alessandro-nori]

Is this a possible security vulnerability?

• This is NOT a possible security vulnerability

Describe the bug

The TaskFileIOSupplier class always tries to get subscoped credentials and doesn't take into consideration the SKIP_CREDENTIAL_SUBSCOPING_INDIRECTION configuration parameter.
In certain setups, we should be able to load a FileIO without credentials.

To Reproduce

Assuming you're using AWS s3 as storage type for your catalog:

1. Set SKIP_CREDENTIAL_SUBSCOPING_INDIRECTION to true and run polaris
2. Send a Purge request from a client that doesn't try to delete the files on the client side (e.g. pyiceberg)
3. Look at the traces and see the call to aws.AssumeRole coming from TaskFileIOSupplier

Actual Behavior

Polaris tries to get subscoped credentials for the FileIO

Expected Behavior

Polaris should load a FileIO without credentials

Additional context

No response

System information

No response