fix(grpc): downgrade connection broken log from error to debug level

[gaius-qi]

Description

This pull request makes a minor adjustment to the logging level in the DfdaemonUploadServerHandler implementation. The change downgrades the log message from error! to debug! and updates the wording for clarity. This helps reduce noise in error logs when a connection is broken, making it easier to focus on more critical issues.

• Changed log level from error! to debug! and updated the message in the connection handling code of dragonfly-client/src/grpc/dfdaemon_upload.rs.

Related Issue

Motivation and Context

Screenshots (if appropriate)

[chlins]

lgtm

[mingcheng]

LGTM

[Copilot]

Pull request overview

This PR reduces log noise in the gRPC upload server by downgrading a “connection broken” log from error! to debug!, reflecting that a closed stream/channel during host sync is typically a normal condition rather than an actionable error.

Changes:

• Downgrade the “connection broken” log in DfdaemonUploadServerHandler::sync_host from error! to debug!
• Refine the log message wording for clarity

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.86%. Comparing base (7d33221) to head (d52e473).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
dragonfly-client/src/grpc/dfdaemon_upload.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1736   +/-   ##
=======================================
  Coverage   46.86%   46.86%           
=======================================
  Files          87       87           
  Lines       24816    24816           
=======================================
  Hits        11629    11629           
  Misses      13187    13187           

Files with missing lines	Coverage Δ
dragonfly-client/src/grpc/dfdaemon_upload.rs	0.00% <0.00%> (ø)

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