chore: retain original headers

[tisonkun]

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?

Copied files need not to contain our own headers, but retain the owner's.

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

All modified and coverable lines are covered by tests ✅

Project coverage is 85.05%. Comparing base (2ad0b24) to head (8d87de3).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3572      +/-   ##
==========================================
- Coverage   85.43%   85.05%   -0.38%     
==========================================
  Files         911      911              
  Lines      152425   152425              
==========================================
- Hits       130220   129645     -575     
- Misses      22205    22780     +575     

[tisonkun]

@evenyag Thanks for your review. The merge queue will rebase on main and test by default so we don't need to update to main manually which run once more CI.

The intention to "Always suggest update branch" is for a fast path merge main to catch up some fixes in other PRs.