chore: do not reply for broadcast msg

[fengjiachun]

I hereby agree to the terms of the GreptimeDB CLA.

Refer to a related PR or issue link (optional)

What's changed and what's your intention?

It is unnecessary to reply to the broadcast msg from metasrv

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR does not require documentation updates.

[codecov]

Codecov Report

Attention: Patch coverage is 81.81818% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 85.01%. Comparing base (5addb7d) to head (a35b8f5).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3595      +/-   ##
==========================================
- Coverage   85.36%   85.01%   -0.36%     
==========================================
  Files         931      931              
  Lines      154702   154611      -91     
==========================================
- Hits       132065   131444     -621     
- Misses      22637    23167     +530