Warn and fix identity conflict when owned entity has inconsistent data in DB

[Copilot]

When a row has NULL in a non-nullable column of an outer owned entity but non-NULL values in nested inner owned entity columns, EF Core silently materializes the outer as null while still tracking the inner entity. Any subsequent SaveChanges after replacing the outer owned entity then throws a misleading InvalidOperationException about an identity conflict.

Root cause

IncludeReference only handles the case where the owner entity is non-null. When the owner is null (due to the inconsistent data), the already-tracked inner entity remains in the state manager as an orphan, causing the identity conflict later.

Changes

• IncludeReference fix (ShaperProcessingExpressionVisitor.ClientMethods.cs): Added an else if branch that detects a null owner with a non-null tracked owned entity on an ownership navigation, then calls IgnoreOrphanedOwnedEntity to detach the orphan.

• QueryContext.IgnoreOrphanedOwnedEntity (new public method): Detaches the orphaned entity from the state manager and logs the warning.

• CoreEventId.InconsistentOwnedDataWarning (new event, Warning level): Surfaced via CoreLoggerExtensions.InconsistentOwnedData. Default behavior (with WarningBehavior.Throw) will throw on inconsistent data; users can configure to Log or Ignore.

• API baseline (EFCore.baseline.json): Updated for the three new public members.

• Test (OwnedEntityQueryRelationalTestBase): Verifies that the warning is logged, Outer is null, and SaveChanges succeeds after replacing the owned entity with a valid instance.

// DB row: (Id=X, Outer_RequiredProperty=NULL, Outer_Inner_InnerProperty=42)
var root = await context.Set<RootEntity>().SingleAsync();
// root.Outer == null  ← was silently null before; now logs InconsistentOwnedDataWarning

root.Outer = new Outer { RequiredProperty = 1, Inner = new Inner { InnerProperty = 2 } };
await context.SaveChangesAsync(); // ← previously threw InvalidOperationException (identity conflict)