Reduce cfg boilerplate (#7689)

* reduce cfg boilerplate

* fix compile error

* user test fix

* another test fix

* simplify diagnostics / testing

app/channel_test.go

@@ -4,21 +4,16 @@ import (
 	"testing"
 
 	"github.com/mattermost/mattermost-server/model"
-	"github.com/mattermost/mattermost-server/utils"
 )
 
 func TestPermanentDeleteChannel(t *testing.T) {
 	th := Setup().InitBasic()
 	defer th.TearDown()
 
-	incomingWasEnabled := utils.Cfg.ServiceSettings.EnableIncomingWebhooks
-	outgoingWasEnabled := utils.Cfg.ServiceSettings.EnableOutgoingWebhooks
-	utils.Cfg.ServiceSettings.EnableIncomingWebhooks = true
-	utils.Cfg.ServiceSettings.EnableOutgoingWebhooks = true
-	defer func() {
-		utils.Cfg.ServiceSettings.EnableIncomingWebhooks = incomingWasEnabled
-		utils.Cfg.ServiceSettings.EnableOutgoingWebhooks = outgoingWasEnabled
-	}()
+	th.App.UpdateConfig(func(cfg *model.Config) {
+		cfg.ServiceSettings.EnableIncomingWebhooks = true
+		cfg.ServiceSettings.EnableOutgoingWebhooks = true
+	})
 
 	channel, err := th.App.CreateChannel(&model.Channel{DisplayName: "deletion-test", Name: "deletion-test", Type: model.CHANNEL_OPEN, TeamId: th.BasicTeam.Id}, false)
 	if err != nil {