getFeatureInfo (for WMS layers) shows nothing perceivable if one layer does not return proper json

[Grammostola]

If a WMS layer is given the queryable prop value of true but is configured in a way on the server that won't produce an application/json response (such as a cascaded or misconfigured layer) then infoclicking it will currently yield no visible result.

If another properly configured and queryable layer is visible at the same time then clicking on one of its objects will not show an infowindow either (Promise.all)

Some fault tolerance is needed so that the misconfigured layer does not doom the others, like checking if the response is proper json and if not log it, don't throw an error making that Promise.all upset.

Other things I have thought about

Promise.allSettled but that is a slightly longer path. Basic robustness is winner.