MM-10658 Change config fields to pointers (#9033)

* MM 10658 Change config fields to pointers (#8898)

* Change fields of config structs to pointers and set defaults

MM-10658 https://github.com/mattermost/mattermost-server/issues/8841

* Fix tests that go broken during switching config structs to pointers

MM-10658 https://github.com/mattermost/mattermost-server/issues/8841

* Apply changes of current master while switching config structs to pointers

MM-10658 https://github.com/mattermost/mattermost-server/issues/8841

* Fix new config pointer uses

* Fix app tests

* Fix mail test

* remove debugging statement

* fix TestUpdateConfig

* assign config consistently

* initialize AmazonS3Region in TestS3TestConnection

* initialize fields for TestEmailTest

* fix TestCheckMandatoryS3Fields

api4/commands_test.go

@@ -163,12 +163,12 @@ func TestLoadTestHelpCommands(t *testing.T) {
 	Client := th.Client
 	channel := th.BasicChannel
 
-	enableTesting := th.App.Config().ServiceSettings.EnableTesting
+	enableTesting := *th.App.Config().ServiceSettings.EnableTesting
 	defer func() {
-		th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = enableTesting })
+		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = enableTesting })
 	}()
 
-	th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = true })
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = true })
 
 	rs := Client.Must(Client.ExecuteCommand(channel.Id, "/test help")).(*model.CommandResponse)
 	if !strings.Contains(rs.Text, "Mattermost testing commands to help") {
@@ -185,12 +185,12 @@ func TestLoadTestSetupCommands(t *testing.T) {
 	Client := th.Client
 	channel := th.BasicChannel
 
-	enableTesting := th.App.Config().ServiceSettings.EnableTesting
+	enableTesting := *th.App.Config().ServiceSettings.EnableTesting
 	defer func() {
-		th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = enableTesting })
+		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = enableTesting })
 	}()
 
-	th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = true })
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = true })
 
 	rs := Client.Must(Client.ExecuteCommand(channel.Id, "/test setup fuzz 1 1 1")).(*model.CommandResponse)
 	if rs.Text != "Created environment" {
@@ -207,12 +207,12 @@ func TestLoadTestUsersCommands(t *testing.T) {
 	Client := th.Client
 	channel := th.BasicChannel
 
-	enableTesting := th.App.Config().ServiceSettings.EnableTesting
+	enableTesting := *th.App.Config().ServiceSettings.EnableTesting
 	defer func() {
-		th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = enableTesting })
+		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = enableTesting })
 	}()
 
-	th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = true })
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = true })
 
 	rs := Client.Must(Client.ExecuteCommand(channel.Id, "/test users fuzz 1 2")).(*model.CommandResponse)
 	if rs.Text != "Added users" {
@@ -229,12 +229,12 @@ func TestLoadTestChannelsCommands(t *testing.T) {
 	Client := th.Client
 	channel := th.BasicChannel
 
-	enableTesting := th.App.Config().ServiceSettings.EnableTesting
+	enableTesting := *th.App.Config().ServiceSettings.EnableTesting
 	defer func() {
-		th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = enableTesting })
+		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = enableTesting })
 	}()
 
-	th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = true })
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = true })
 
 	rs := Client.Must(Client.ExecuteCommand(channel.Id, "/test channels fuzz 1 2")).(*model.CommandResponse)
 	if rs.Text != "Added channels" {
@@ -251,12 +251,12 @@ func TestLoadTestPostsCommands(t *testing.T) {
 	Client := th.Client
 	channel := th.BasicChannel
 
-	enableTesting := th.App.Config().ServiceSettings.EnableTesting
+	enableTesting := *th.App.Config().ServiceSettings.EnableTesting
 	defer func() {
-		th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = enableTesting })
+		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = enableTesting })
 	}()
 
-	th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableTesting = true })
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableTesting = true })
 
 	rs := Client.Must(Client.ExecuteCommand(channel.Id, "/test posts fuzz 2 3 2")).(*model.CommandResponse)
 	if rs.Text != "Added posts" {