fix: Remove single quotes from test (#329)

The `GetFiles_MissingDirectory_ShouldThrowDirectoryNotFoundException`
test failed because exceptions are thrown in German on my system and
with double quotes, therefore I deleted the quotes from the assertion.

Co-authored-by: Stefan Lampert <[email protected]>
Co-authored-by: Valentin Breuß <[email protected]>

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

@@ -21,7 +21,7 @@ public void
 			Record.Exception(()
 				=> FileSystem.Directory.GetFiles(path).ToList());
 
-		exception.Should().BeException<DirectoryNotFoundException>($"'{expectedPath}'.",
+		exception.Should().BeException<DirectoryNotFoundException>(expectedPath,
 			hResult: -2147024893);
 		FileSystem.Directory.Exists(path).Should().BeFalse();
 	}