[skip-changelog] Fix copySketch testsuite function (#1918)

The original copy sketch function written in conftest.py copies sketches into the testsuite's working directory. Changing the copy sketch function present in the golang testsuite to match the original one,
should prevent errors that could occur while migrating tests.

internal/integrationtest/arduino-cli.go

@@ -152,7 +152,7 @@ func (cli *ArduinoCLI) CopySketch(sketchName string) *paths.Path {
 	cli.t.NoError(err)
 	cli.t.NotNil(p)
 	testSketch := p.Parent().Join("testdata", sketchName)
-	sketchPath := cli.SketchbookDir().Join(sketchName)
+	sketchPath := cli.WorkingDir().Join(sketchName)
 	err = testSketch.CopyDirTo(sketchPath)
 	cli.t.NoError(err)
 	return sketchPath