Support for random UUID v7

### Description

NET 9 natively supports UUID v7. I would like to be able to generate deterministic UUIDs based on version 7 timestamps for my database.

### LINQPad Code Example

```csharp
new Faker().Random.Guid(version: GuidVersion.Version7);
```
or
```csharp
new Faker().Random.GuidVersion7();
```

### What alternatives have you considered?

No.

### Could you help with a pull-request?

No

The requested entry points are Random.Guid(version: GuidVersion.Version7) and Random.GuidVersion7(); start by tracing those APIs and how UUID versions are currently handled. Done means UUID v7 generation is available on .NET 9 and the provided LINQPad examples work, including the requested deterministic timestamp-based behavior.

Written by the indexing model from the issue text.