1. Proposed title of this feature request

Successful Image Pull Pre-Check in connected environment 

2. What is the nature and description of the request?

While upgrading the cluster,  ensure that all container images that was  needed to perform a successful upgrade, can be downloaded successfully from the Internet prior to proceeding with the upgrade process. This would ensure that a cluster upgrade doesn't stall midway through the patching process due to un-fetchable container images.

3. Why does the customer need this? (List the business requirements here)

During an upgrade from OpenShift 4.12.40 to 4.12.47 customer faced  issues while pulling specific OpenShift container image blobs from quay.io. After a quick troubleshooting session, they were able to identify that these failures were caused by some common enterprise wide Internet Proxying infrastructure. Since some, but not all of the OpenShift container images could be successfully sourced from quay.io the upgrade stalled.

4. List any affected packages or components.