Pop!_Shop should provide Run option when searching for a program already installed

[brs17]

If this is a bug, please use the template below. If this is a feature request, question, or a general discussion topic - please post on our subreddit https://reddit.com/r/pop_os - as that is the proper forum for those types of posts.

 * Distribution - (run ```cat /etc/os-release```)
 * Related Application and/or Package Version - apt policy $PACKAGE NAME

Pop!_OS 17.10

Issue/Bug Description Under the "Home" tab, when searching for a program that is already installed on the system, there should be an "Open" button to open the program.

Currently:

Desired:

[isantop]

This issue was moved to pop-os/shop#23