Per-metric relativization for Summary with preference metrics

[ItsMrLin]

Summary:

Summary

Supersedes D97533888. Addresses drfreund's review comment about deduping with Data.relativize by placing the per-metric scoping in the data layer rather than adding analysis-specific logic.

When an experiment has both preference metrics (e.g., pairwise_pref_query) and standard tracking metrics, the Summary should relativize tracking metrics normally while skipping the preference metric (whose binary 0/1 labels have SQ mean near zero, causing "mean_control too small" crash).

Previously D99037272 applied a blanket guard that skipped ALL relativization when any objective was a preference metric. This diff replaces that with per-metric scoping: non-preference metrics are relativized and %-formatted, while preference metrics are excluded from relativization and their columns are dropped from the summary table (binary 0/1 labels are not informative in a tabular summary). Labeling-only trial rows (with no tracking metric data) are also dropped.

Changes:

• Data.relativize() and relativize_dataframe() in ax/core/data.py: add metric_names parameter to scope which metrics get relativized. Unscoped metrics pass through with raw values. SEM zeroing for status quo rows is also scoped -- non-relativized metrics retain their original SEM.
• Experiment.to_df() in ax/core/experiment.py: add metric_names_to_relativize parameter, threaded to Data.relativize(). Percentage formatting also scoped to only relativized metrics.
• Summary.compute() in ax/analysis/summary.py: replace blanket not has_preference_objective guard with per-metric scoping. Builds a list of non-preference metric names, passes it as metric_names_to_relativize, then drops preference columns and labeling-only rows.

Differential Revision: D99149923

[meta-codesync]

@ItsMrLin has exported this pull request. If you are a Meta employee, you can view the originating Diff in D99149923.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.59155% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 96.50%. Comparing base (d0ae700) to head (05bb9a8).

Files with missing lines	Patch %	Lines
ax/core/data.py	92.30%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5218   +/-   ##
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  Coverage   96.50%   96.50%           
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  Files         617      617           
  Lines       69776    69833   +57     
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+ Hits        67339    67395   +56     
- Misses       2437     2438    +1     

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[meta-codesync]

This pull request has been merged in c40dfae.