feat: remove redirect stderr to file

[gaius-qi]

Description

This pull request includes several changes to the dragonfly-client project, focusing on dependency updates and code cleanup. The most important changes include the removal of the libc dependency, cleanup of unused imports, and the removal of the redirect_stderr_to_file function.

Dependency updates:

• dragonfly-client/Cargo.toml: Removed the libc dependency.

Code cleanup:

• dragonfly-client/src/tracing/mod.rs: Removed unused imports OpenOptions and AsRawFd.
• dragonfly-client/src/tracing/mod.rs: Removed the redirect_stderr_to_file function and related code that redirected stderr to a file.

Related Issue

Motivation and Context

Screenshots (if appropriate)

[chlins]

lgtm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 34.47%. Comparing base (7e9ccae) to head (076403a).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #938      +/-   ##
==========================================
+ Coverage   34.42%   34.47%   +0.05%     
==========================================
  Files          60       60              
  Lines        9293     9278      -15     
==========================================
  Hits         3199     3199              
+ Misses       6094     6079      -15     

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

[fcgxz2003]

LGTM