SignalR: IUserIDProvider: show how to identify the hub being accessed

This doc issue is related to product issue discussion here, see for more details:
[IUserIdProvider peer Hub 13021 ](https://github.com/dotnet/aspnetcore/issues/13021)

IUserIDProvider documentation needs to show how to identify the hub being accessed.

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#### Document Details

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* ID: d0da2144-3730-f8ef-1d16-a89f11fd6198
* Version Independent ID: 6d8f5bc8-8f5c-ba13-b7f2-0366eac46f81
* Content: [Authentication and authorization in ASP.NET Core SignalR](https://learn.microsoft.com/en-us/aspnet/core/signalr/authn-and-authz?view=aspnetcore-7.0&viewFallbackFrom=aspnetcore-2.2#use-claims-to-customize-identity-handling)
* Content Source: [aspnetcore/signalr/authn-and-authz.md](https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/signalr/authn-and-authz.md)
* Product: **aspnet-core**
* Technology: **aspnetcore-signalr**
* GitHub Login: @bradygaster
* Microsoft Alias: **bradyg**

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[Associated WorkItem - 66679](https://dev.azure.com/msft-skilling/Content/_workitems/edit/66679)