Choco List command gives unexpected output when run against none existing source

### What You Are Seeing?

When running choco list against a source that is not configured within the config of chocolatey sources on the machine the output of the command is "0 packages found."

### What is Expected?

If you try to run a choco list against a source that is not configured on your machine the output should say source not configured on machine, please reference output of `choco source list`

### How Did You Get This To Happen? (Steps to Reproduce)

Run `choco list -s ` with a source that is not configured within Chocolatey on the machine and you will get "0 packages found." for output.

### Output Log

Start by tracing the `choco list -s ` command's handling of source lookup, then compare it with the output behavior of `choco source list`. The change is complete when an unconfigured source reports that it is not configured instead of showing "0 packages found."

Written by the indexing model from the issue text.