Fix non-deterministic NuGet packages by enabling ContinuousIntegrationBuild for OneBranch builds

[apoorvdeshmukh]

Description

Restore deterministic builds for OneBranch-produced NuGet packages so they pass NuGet Package Explorer's "Deterministic (build)" check.
Introduced a BuildForRelease gate in src/Directory.Build.props that drives ContinuousIntegrationBuild. The two OneBranch pipelines set BuildForRelease: true; PR/CI and local dev builds are unchanged.

Testing

The official and non-official run should validate this change.

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[Copilot]

Pull request overview

This PR restores deterministic OneBranch-produced NuGet packages by introducing a BuildForRelease MSBuild property (defaulting to false) and using it to drive ContinuousIntegrationBuild for OneBranch builds, enabling portable source paths in embedded PDBs.

Changes:

• Add BuildForRelease to src/Directory.Build.props and default ContinuousIntegrationBuild to $(BuildForRelease) when not explicitly set.
• Set BuildForRelease: true in the OneBranch official pipeline.
• Set BuildForRelease: true in the OneBranch non-official pipeline to exercise the deterministic build path.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/Directory.Build.props	Introduces BuildForRelease and gates ContinuousIntegrationBuild defaults to enable deterministic source paths for release builds.
eng/pipelines/onebranch/sqlclient-official.yml	Sets BuildForRelease=true for official OneBranch builds.
eng/pipelines/onebranch/sqlclient-non-official.yml	Sets BuildForRelease=true for non-official OneBranch builds to validate determinism in pre-release runs.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.29%. Comparing base (061c45b) to head (d26db38).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4251      +/-   ##
==========================================
- Coverage   66.05%   64.29%   -1.76%     
==========================================
  Files         277      272       -5     
  Lines       42988    65783   +22795     
==========================================
+ Hits        28396    42297   +13901     
- Misses      14592    23486    +8894     

Flag	Coverage Δ
CI-SqlClient	?
PR-SqlClient-Project	64.29% <ø> (?)

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