.NET: Fix sample resource path resolution

[westey-m]

Motivation and Context

The samples were working when run from Visual Studio, but failing when using dotnet run due to the difference in the path from which they were executed.

Description

• Change resource resolution to be relative to the executable's path.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull request overview

This PR updates .NET GettingStarted workflow samples to load text resources relative to the executable output directory (instead of the current working directory), fixing failures when running via dotnet run.

Changes:

• Switch resource file loading from a relative path (Resources/...) to Path.Combine(AppContext.BaseDirectory, "Resources", ...) across affected samples.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
dotnet/samples/GettingStarted/Workflows/SharedStates/Resources.cs	Reads resources from the app base directory to work under dotnet run.
dotnet/samples/GettingStarted/Workflows/ConditionalEdges/01_EdgeCondition/Resources.cs	Same base-directory resource resolution change for this sample.
dotnet/samples/GettingStarted/Workflows/ConditionalEdges/02_SwitchCase/Resources.cs	Same base-directory resource resolution change for this sample.
dotnet/samples/GettingStarted/Workflows/ConditionalEdges/03_MultiSelection/Resources.cs	Same base-directory resource resolution change for this sample.