[release/10.0] Fix TableSharingConcurrencyTokenConvention to skip JSON-mapped entities

[Copilot]

Fixes #37274

Description
The TableSharingConcurrencyTokenConvention was incorrectly adding shadow concurrency token properties to JSON-mapped owned entities causing model validation to fail.

// This fails in EF Core 10 but worked in 9.x
public abstract class BaseEntity
{
    public int Id { get; set; }
    public long RowVersion { get; set; } // IsRowVersion
}

public class DerivedEntity : BaseEntity
{
    public OwnedEntity Owned { get; set; } // Mapped with ToJson()
}

Customer impact
Apps using TPH inheritance with a concurrency token in the base class and a JSON-mapped owned entity in a derived class get an exception during model building. There is no known workaround other than removing either the concurrency token or the JSON mapping.

How found
Customer reported on EF 10. Not a common scenario.

Regression
Yes, from EF Core 9.x.

Testing
Test added.

Risk
Low. Targeted fix for the affected scenario.

Original prompt

Fix #37274

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[AndriySvyryd]

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Fixes #{number}

**Description**
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**Customer impact**
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**How found**
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**Regression**
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[Copilot]

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[AndriySvyryd]

cc @artl93