FeatureFlags: Cleanup usage of cfg.IsFeatureToggleEnabled (#78014)

pkg/setting/setting.go

@@ -980,9 +980,22 @@ func NewCfg() *Cfg {
 		Logger: log.New("settings"),
 		Raw:    ini.Empty(),
 		Azure:  &azsettings.AzureSettings{},
+
+		// Avoid nil pointer
+		IsFeatureToggleEnabled: func(_ string) bool {
+			return false
+		},
 	}
 }
 
+// Deprecated: Avoid using IsFeatureToggleEnabled from settings.  If you need to access
+// feature flags, read them from the FeatureToggle (or FeatureManager) interface
+func NewCfgWithFeatures(features func(string) bool) *Cfg {
+	cfg := NewCfg()
+	cfg.IsFeatureToggleEnabled = features
+	return cfg
+}
+
 func NewCfgFromArgs(args CommandLineArgs) (*Cfg, error) {
 	cfg := NewCfg()
 	if err := cfg.Load(args); err != nil {