Auth: Use authn.Service for all tests (#72921)

* Dashboards: Fix tests when authn broker is enabled.
StarService was not configured for tests, the call was guarded by !c.IsSignedIn

* Change default to be anon user to match expectations from tests

* OAuth: rewrite tests to work with authn.Service

* Setup template renderer by default

* Extract cookie options from cfg instead of relying on global variables

* Fix test to work with authn service

* Middleware: rewrite auth tests

* Remvoe session cookie if we cannot refresh access token

pkg/setting/setting.go

@@ -968,11 +968,12 @@ var skipStaticRootValidation = false
 
 func NewCfg() *Cfg {
 	return &Cfg{
-		Target:      []string{},
-		Logger:      log.New("settings"),
-		Raw:         ini.Empty(),
-		Azure:       &azsettings.AzureSettings{},
-		RBACEnabled: true,
+		Target:            []string{},
+		Logger:            log.New("settings"),
+		Raw:               ini.Empty(),
+		Azure:             &azsettings.AzureSettings{},
+		RBACEnabled:       true,
+		AuthBrokerEnabled: true,
 	}
 }