Reduce utils.Cfg references (#7650)

* app.UpdateConfig method

* test fix

* another test fix

* the config override option as-was is just error prone, remove it for now

* derp

app/app.go

@@ -47,8 +47,7 @@ type App struct {
 	Mfa              einterfaces.MfaInterface
 	Saml             einterfaces.SamlInterface
 
-	newStore       func() store.Store
-	configOverride func(*model.Config) *model.Config
+	newStore func() store.Store
 }
 
 var appCount = 0
@@ -234,12 +233,13 @@ func (a *App) initEnterprise() {
 }
 
 func (a *App) Config() *model.Config {
-	if a.configOverride != nil {
-		return a.configOverride(utils.Cfg)
-	}
 	return utils.Cfg
 }
 
+func (a *App) UpdateConfig(f func(*model.Config)) {
+	f(utils.Cfg)
+}
+
 // Go creates a goroutine, but maintains a record of it to ensure that execution completes before
 // the app is destroyed.
 func (a *App) Go(f func()) {