chore: query prom using input query context

[shuiyisong]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

This pr mainly fixes a issue where prom handler uses QueryContext::arc() instead of actual input catalog and schema

@MichaelScofield
Also, I think we should check every non-test call to QueryContext::arc(). It shouldn't be called now that we have parsed catalog and schema from user input. I'll do this in a separate pr if you're ok with it

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #1381 (38a72f0) into develop (0fc816f) will decrease coverage by 0.42%.
The diff coverage is 90.90%.

@@             Coverage Diff             @@
##           develop    #1381      +/-   ##
===========================================
- Coverage    86.05%   85.64%   -0.42%     
===========================================
  Files          529      529              
  Lines        78771    78783      +12     
===========================================
- Hits         67787    67470     -317     
- Misses       10984    11313     +329     

[fengys1996]

LGTM