Ensure no exceptions are thrown when handling UI banners
Ensure no exceptions are thrown when handling UI banners

Any exceptions during JSON parsing are now handled; fields are checked
for being a string; logic was slightly consolidated.

rancherio/ui,vincent99/ui,rancher/ui,rancherio/ui,vincent99/ui,rancher/ui,rancherio/ui,westlywright/ui,vincent99/ui,westlywright/ui,rancher/ui,westlywright/ui