fix: wrong handler implementation of prometheus remote write

[waynexia]

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?

To be honest, this part is awful. Four almost identical functions with only two booleans different.

I tried to refactor them with const generic but axum doesn't support function handler with const generic yet tokio-rs/axum#1265. Using macro is another option but given this part is not likely to change and macro is also not perfect to my perspective, I leave it as is and only fix the wrong param.

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 14.28571% with 36 lines in your changes are missing coverage. Please review.

Project coverage is 85.49%. Comparing base (f29aebf) to head (05a046d).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3826      +/-   ##
==========================================
- Coverage   85.77%   85.49%   -0.29%     
==========================================
  Files         952      952              
  Lines      162629   162686      +57     
==========================================
- Hits       139492   139084     -408     
- Misses      23137    23602     +465     

[tisonkun]

Thank you!