Add batch error handling to Notifications page

[jpellizzari]

Closes #3634

Adds an ErrorList component to Core, heavily inspired by the one used in EE. This also exports the ErrorList component so that it may be imported in EE and eventually subsume the AlertListErrors component (there is nothing wrong with that component currently, but this will enforce Consistency:tm:).

There are now two error "classes" on the page:

Error when we can't reach the backend:

Batched errors from various clusters (backend returns lots of errors):

Simulated the error state using this:

 core/server/objects.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/core/server/objects.go b/core/server/objects.go
index 0bb6e26d5..f99290bbc 100644
--- a/core/server/objects.go
+++ b/core/server/objects.go
@@ -14,6 +14,7 @@ import (
 	pb "github.com/weaveworks/weave-gitops/pkg/api/core"
 	"github.com/weaveworks/weave-gitops/pkg/run/constants"
 	"github.com/weaveworks/weave-gitops/pkg/server/auth"
+	"github.com/weaveworks/weave-gitops/pkg/utils"
 	v1 "k8s.io/api/apps/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -148,6 +149,15 @@ func (cs *coreServer) ListObjects(ctx context.Context, msg *pb.ListObjectsReques
 		}
 	}
 
+	if msg.Kind == "Provider" {
+
+		for i := 0; i < 50; i++ {
+			msg, _ := utils.GenerateRandomString(5, 10)
+			respErrors = append(respErrors, &pb.ListError{ClusterName: "provider", Message: fmt.Sprintf("such and such is forbidden in namespace: %v", msg)})
+		}
+
+	}
+
 	return &pb.ListObjectsResponse{
 		Objects: results,
 		Errors:  respErrors,

[jpellizzari]

Authoring the PR made me realize the Alert icons are inconsistent, so I fixed that in a second commit:

[joshri]

LGTM - might be worth distinguishing between the request errors and permissions errors somehow...maybe permissions errors are more like warnings? Just a thought for the future

[jpellizzari]

LGTM - might be worth distinguishing between the request errors and permissions errors somehow...maybe permissions errors are more like warnings? Just a thought for the future

I think "errors is errors" as far as the backend is concerned. It doesn't differentiate between permissions and request errors.