insights: skip any search contexts that fail to load instead of erroring
Created by: coury-clark
Part of https://github.com/sourcegraph/sourcegraph/issues/38951
When loading an insight, skip any search contexts that fail to load. These will not be propagated to the UI at the moment, but will prevent the entire load from breaking.
Test plan
Before: https://user-images.githubusercontent.com/5090588/179565459-0ea9aba6-5513-49dd-9e01-aa97718f3327.png