chore : Deprecating FeatureToggles.IsEnabled (#113062)

* Deprecating features.IsEnabled

* add one more nolint

* add one more nolint

* Give better hints to devs in the deprecation message of IsEnabledGlobally

* adding more doc strings

* fix linter after rebase

* Extend deprecation message

pkg/api/index.go

@@ -62,6 +62,7 @@ func (hs *HTTPServer) setIndexViewData(c *contextmodel.ReqContext) (*dtos.IndexV
 		return nil, err
 	}
 
+	//nolint:staticcheck // not yet migrated to OpenFeature
 	if hs.Features.IsEnabled(c.Req.Context(), featuremgmt.FlagIndividualCookiePreferences) {
 		if !prefs.Cookies("analytics") {
 			settings.GoogleAnalytics4Id = ""
@@ -94,6 +95,7 @@ func (hs *HTTPServer) setIndexViewData(c *contextmodel.ReqContext) (*dtos.IndexV
 	}
 
 	var regionalFormat string
+	//nolint:staticcheck // not yet migrated to OpenFeature
 	if hs.Features.IsEnabled(c.Req.Context(), featuremgmt.FlagLocaleFormatPreference) {
 		regionalFormat = "en"