feat: Fix output bytes metric in hash agg

[ariel-miculas]

Which issue does this PR close?

Alternative POC to #23777

• Closes Incorrect output_bytes metric in hash aggregation #23776.

Rationale for this change

Summing together the produced sliced RecordBatches in hash aggregation leads to inflated output_bytes metric

What changes are included in this PR?

What is the testing strategy for this PR?

sqllogic test and unit tests

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 87.73006% with 20 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.74%. Comparing base (57740ca) to head (a1c65f0).
⚠️ Report is 16 commits behind head on main.

Files with missing lines	Patch %	Lines
datafusion/physical-plan/src/aggregates/mod.rs	87.39%	2 Missing and 13 partials ⚠️
...usion/physical-expr-common/src/metrics/baseline.rs	57.14%	3 Missing ⚠️
...fusion/physical-plan/src/aggregates/hash_stream.rs	77.77%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #25086      +/-   ##
==========================================
+ Coverage   81.71%   81.74%   +0.03%     
==========================================
  Files        1127     1128       +1     
  Lines      416072   416782     +710     
  Branches   416072   416782     +710     
==========================================
+ Hits       339993   340708     +715     
+ Misses      56091    56001      -90     
- Partials    19988    20073      +85     

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