fix: remove noisy stderr prints in ERA1 cleanup (EraClient::delete_outside_range)

[sashaodessa]

Summary

Remove two eprintln! calls from library code to avoid noisy stderr output during ERA1 file cleanup.

Why

• Library code should not write directly to stderr.
• Unnecessary prints pollute CLI/test output and bypass the project’s logging (tracing).

Changes

• Delete two eprintln! lines in crates/era-downloader/src/client.rs within EraClient::delete_outside_range.