ForeignKeyPropertyDiscoveryConvention doesn't trigger when a shadow property is added that matches the property created implicitly

[AndriySvyryd]

This causes the principal side to remain ambiguous when it shouldn't be.

See

efcore/test/EFCore.Tests/ModelBuilding/TestModel.cs

Line 371 in b7f8860

// TODO: Make both non-nullable when #25830 is fixed

This might be easier to fix after #15898 is implemented

[AndriySvyryd]

Fixed in 9952893