Only do docker run when the image exists

[kienstra]

The Final Terminal does docker run to get bash access to the committed image:

local-ci/src/utils.ts

Line 255 in d084b50

`docker run -it --rm ${committedContainerBase}${jobName}`

But if the CircleCI job passed or failed too soon, there might not be an image.

Then, there will be an error:

* Cannot find a job named `test_php74` to run in the `jobs:` section of your configuration file.

Instead, maybe there should be no Final Terminal, or it should open with a message that it couldn't debug the job.

[kienstra]

This could probably use an if conditional around it to check that it has an image.