feat: add ProblemInstanceException

Also add `EnsureSuccess` to `Result<T>`.

src/Altinn.Authorization.ProblemDetails/src/ProblemDetails.Abstractions/ProblemInstanceException.cs

@@ -0,0 +1,23 @@
+namespace Altinn.Authorization.ProblemDetails;
+
+/// <summary>
+/// An exception that represents a <see cref="ProblemInstance"/>.
+/// </summary>
+public class ProblemInstanceException
+    : InvalidOperationException
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ProblemInstanceException"/> class.
+    /// </summary>
+    /// <param name="problemInstance">The <see cref="ProblemInstance"/>.</param>
+    public ProblemInstanceException(ProblemInstance problemInstance)
+        : base(problemInstance.Detail)
+    {
+        ProblemInstance = problemInstance;
+    }
+
+    /// <summary>
+    /// Gets the <see cref="ProblemInstance"/>.
+    /// </summary>
+    public ProblemInstance ProblemInstance { get; }
+}

src/Altinn.Authorization.ProblemDetails/src/ProblemDetails.Abstractions/Result.cs

@@ -49,6 +49,19 @@ public bool IsSuccess
         get => _problem is null;
     }
 
+    /// <summary>
+    /// Ensures that the operation succeeded.
+    /// </summary>
+    /// <exception cref="ProblemInstanceException">Thrown if the operation failed.</exception>
+    [MemberNotNull(nameof(Value))]
+    public void EnsureSuccess()
+    {
+        if (!IsSuccess)
+        {
+            throw new ProblemInstanceException(_problem!);
+        }
+    }
+
     /// <summary>
     /// Gets the problem instance if the operation failed, otherwise <see langword="null"/>.
     /// </summary>