Chore: Remove newNavigation feature toggle and old navbar code (#50872)

* Remove newNavigation feature toggle + old code

* fix unit tests

* remove buildCreateNavLinks

pkg/services/featuremgmt/registry.go

@@ -95,11 +95,6 @@ var (
 			State:        FeatureStateAlpha,
 			FrontendOnly: true,
 		},
-		{
-			Name:        "newNavigation",
-			Description: "Try the next gen navigation model",
-			State:       FeatureStateAlpha,
-		},
 		{
 			Name:            "showFeatureFlagsInUI",
 			Description:     "Show feature flags in the settings UI",

pkg/services/featuremgmt/toggles_gen.go

@@ -71,10 +71,6 @@ const (
 	// Query InfluxDB InfluxQL without the proxy
 	FlagInfluxdbBackendMigration = "influxdbBackendMigration"
 
-	// FlagNewNavigation
-	// Try the next gen navigation model
-	FlagNewNavigation = "newNavigation"
-
 	// FlagShowFeatureFlagsInUI
 	// Show feature flags in the settings UI
 	FlagShowFeatureFlagsInUI = "showFeatureFlagsInUI"