Bump Go version to 1.23.6 (#30242)

* Bump Go version to 1.23.6

* Update CodeQL Github action as well

* Use server's Go version for CodeQL action

Co-authored-by: Antonis Stamatiou <stamatiou.antonis@gmail.com>

* Empty commit to trigger CI

* Bump golangci-lint to a version supporting Go 1.23

* Fix golangci-lint warnings

Several rules from gosimple, revive and staticcheck linters were
failing:
- Redefinition of built-in identifiers (max, min, new, recover...)
- Use of printf-like functions with simple strings
- Check for nil slices, when len already takes it into account

---------

Co-authored-by: Antonis Stamatiou <stamatiou.antonis@gmail.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/import_utils.go

@@ -16,8 +16,8 @@ const (
 	passwordAllChars         = passwordSpecialChars + passwordNumbers + passwordUpperCaseLetters + passwordLowerCaseLetters
 )
 
-func randInt(max int) (int, error) {
-	val, err := rand.Int(rand.Reader, big.NewInt(int64(max)))
+func randInt(maxInt int) (int, error) {
+	val, err := rand.Int(rand.Reader, big.NewInt(int64(maxInt)))
 	if err != nil {
 		return 0, err
 	}