Replace deprecated ioutil with io and os (#20776)

* Replace ioutil with io and os

* Replace ioutil in utils/file.go

* Minor fix to tests and excluded files

Co-authored-by: Tim Scheuermann <tim.scheuermann@mattermost.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/apitestlib.go

@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"net"
 	"net/http"
@@ -84,7 +83,7 @@ func SetMainHelper(mh *testlib.MainHelper) {
 
 func setupTestHelper(dbStore store.Store, searchEngine *searchengine.Broker, enterprise bool, includeCache bool,
 	updateConfig func(*model.Config), options []app.Option) *TestHelper {
-	tempWorkspace, err := ioutil.TempDir("", "apptest")
+	tempWorkspace, err := os.MkdirTemp("", "apptest")
 	if err != nil {
 		panic(err)
 	}