Add an example how Connection Resiliency can work with a System TransactionScope

The documentation states that Connection Resiliency does not work with transactions by default.
However an example for working with an existing `System.TransactionScope` or `System.Transaction` is missing.
Providing an external `Transaction` is an important scenario for distributed transactions across multiple databases / servers.

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#### Document Details

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* ID: 876c88d4-2972-d905-28d7-56f9e589f309
* Version Independent ID: 29002343-fa42-2f49-3362-53592039b26d
* Content: [Connection Resiliency - EF Core](https://learn.microsoft.com/en-us/ef/core/miscellaneous/connection-resiliency)
* Content Source: [entity-framework/core/miscellaneous/connection-resiliency.md](https://github.com/dotnet/EntityFramework.Docs/blob/main/entity-framework/core/miscellaneous/connection-resiliency.md)
* Product: **entity-framework**
* Technology: **entity-framework-core**
* GitHub Login: @AndriySvyryd
* Microsoft Alias: **avickers**