refactor: move some costly methods in DataBuffer::read out of read lock

[v0y4g3r]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

This PR moves the costly sort and dedup operation inside read_data_buffer_to_record_batch function out of the read lock of Partition.

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.

Refer to a related PR or issue link (optional)

• Tracking issue for the memtable improvement #2804

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.61%. Comparing base (dc205a2) to head (97d3d45).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3406      +/-   ##
==========================================
- Coverage   85.07%   84.61%   -0.46%     
==========================================
  Files         889      889              
  Lines      146377   146280      -97     
==========================================
- Hits       124525   123778     -747     
- Misses      21852    22502     +650     

[evenyag]

LGTM