refactor(k8s): namespace core logic (#12142)

Co-authored-by: testA113 <aliharriss1995@gmail.com>
Co-authored-by: Anthony Lapenna <anthony.lapenna@portainer.io>
Co-authored-by: James Carppe <85850129+jamescarppe@users.noreply.github.com>
Co-authored-by: Ali <83188384+testA113@users.noreply.github.com>

api/http/handler/stacks/stack_associate.go

@@ -1,11 +1,11 @@
 package stacks
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"time"
 
-	"github.com/pkg/errors"
 	portainer "github.com/portainer/portainer/api"
 	"github.com/portainer/portainer/api/http/security"
 	"github.com/portainer/portainer/api/stacks/stackutils"
@@ -95,7 +95,7 @@ func (handler *Handler) stackAssociate(w http.ResponseWriter, r *http.Request) *
 		return httperror.InternalServerError("Unable to verify user authorizations to validate stack deletion", err)
 	}
 	if !canManage {
-		errMsg := "stack management is disabled for non-admin users"
+		errMsg := "Stack management is disabled for non-admin users"
 		return httperror.Forbidden(errMsg, errors.New(errMsg))
 	}