do not loop forever when message when Gateway API is not available

[joaquimrocha]

See #2504 (comment) for context.
Like other views, we need to account for whether this is resource is available.

[farodin91]

@joaquimrocha Do you any link how it is done in different locations?

[joaquimrocha]

The useList function, which we use for most listings, returns results as null till the fetching is done. After that, if there's an error, we display it (otherwise the results are shown). E.g.:

headlamp/frontend/src/components/common/Resource/ResourceTable.tsx

Line 148 in be9e66b

const { items, error, clusterErrors } = resourceClass.useList({ namespace: useNamespaces() });

headlamp/frontend/src/components/common/Resource/ResourceTable.tsx

Line 164 in be9e66b

errorMessage={resourceClass.getErrorMessage(error)}

[joaquimrocha]

@farodin91 Let me know if you are taking a look or whether you prefer us to do it. Cheers.

[farodin91]

I'll try checkout these ideas in the evening.