Chore: Fix error handling in postDashboard, remove UserDisplayDTO, fix live redis client initialization (#87206)

* clean up error handling in postDashboard and remove UserDisplayDTO

* replace GetUserUID with GetUID and GetNamespacedUID, enforce namespace constant type

* lint fix

* lint fix

* more lint fixes

pkg/services/auth/idimpl/service.go

@@ -82,7 +82,7 @@ func (s *Service) SignIdentity(ctx context.Context, id identity.Requester) (stri
 			Claims: jwt.Claims{
 				Issuer:   s.cfg.AppURL,
 				Audience: getAudience(id.GetOrgID()),
-				Subject:  getSubject(namespace, identifier),
+				Subject:  getSubject(namespace.String(), identifier),
 				Expiry:   jwt.NewNumericDate(now.Add(tokenTTL)),
 				IssuedAt: jwt.NewNumericDate(now),
 			},