Brief summary of the bug. What is it ? Where is it ?

When we fetch the URLs to display in the app switcher, it is possible that a URL is returned for which we don't have a corresponding AppName enum. In this case, the url gets mapped to a null key, which is later resulting in a NPE and stopping Optimize from starting successfully.

ATs:

• Optimize can still start successfully even if a URL is returned that is not registered as a known AppName