fix: Delete directory recursive should delete files in subfolders (#422)

Calling `MockFileSystem.Directory.Delete` with `recursive: true` throws
a `DirectoryNotEmptyException` when trying to delete a directory with
files in it.

As the documentation of [`Directory.Delete(String,
Boolean)`](https://learn.microsoft.com/en-us/dotnet/api/system.io.directory.delete?view=net-8.0#system-io-directory-delete(system-string-system-boolean))
indicates, the method should actually try to delete all files and
subfolders instead.

---------

Co-authored-by: Stefan Lampert <s.lampert@tig.at>

Source/Testably.Abstractions.Testing/Storage/InMemoryStorage.cs

@@ -124,7 +124,7 @@ public bool DeleteContainer(IStorageLocation location, bool recursive = false)
 			{
 				foreach (IStorageLocation key in children)
 				{
-					DeleteContainer(key);
+					DeleteContainer(key, recursive);
 				}
 			}
 			else if (children.Any())

Tests/Testably.Abstractions.Tests/FileSystem/Directory/DeleteTests.cs

@@ -147,6 +147,30 @@ public void Delete_Recursive_WithSubdirectory_ShouldDeleteDirectoryWithContent(
 		FileSystem.Should().NotHaveDirectory(subdirectoryPath);
 	}
 
+	[SkippableTheory]
+	[AutoData]
+	public void Delete_Recursive_WithFileInSubdirectory_ShouldDeleteDirectoryWithContent(
+		string path, string subdirectory, string fileName, string fileContent)
+	{
+		FileSystem.Directory.CreateDirectory(path);
+		string filePath = FileSystem.Path.Combine(path, fileName);
+		FileSystem.File.WriteAllText(filePath, fileContent);
+
+		string subdirectoryPath = FileSystem.Path.Combine(path, subdirectory);
+		FileSystem.Directory.CreateDirectory(subdirectoryPath);
+		string subdirectoryFilePath = FileSystem.Path.Combine(path, subdirectory, fileName);
+		FileSystem.File.WriteAllText(subdirectoryFilePath, fileContent);
+
+		FileSystem.Should().HaveDirectory(path);
+
+		FileSystem.Directory.Delete(path, true);
+
+		FileSystem.Should().NotHaveDirectory(path);
+		FileSystem.Should().NotHaveFile(filePath);
+		FileSystem.Should().NotHaveDirectory(subdirectoryPath);
+		FileSystem.Should().NotHaveFile(subdirectoryFilePath);
+	}
+
 	[SkippableTheory]
 	[AutoData]
 	public void Delete_ShouldAdjustTimes(string path, string subdirectoryName)