fix(api): Fix incorrect tag name used to check for the existence of built docker images

[deadlycoconuts]

Context

Following up on the changes to edit the naming convention of docker images built by the Turing API server in PR #368, this PR introduces a tiny fix to a part of the image building process that checks for the existence of a docker image with the same tag.

Previously the tag was left as the ensembler id, which is incorrectly, given the changes proposed in PR #368. This PR corrects the image tag used for the check mentioned above to the ensembler run id. Here's a recap of how the changes should look like:

Before

{dockerRegistry}/{projectName}-{ensemblerName}-{runID}-service:{ensemblerID}

or

{dockerRegistry}/{projectName}-{ensemblerName}-{runID}-job:{ensemblerID}

After

{dockerRegistry}/{projectName}/ensembler-services/{ensemblerName}:{runID}

or

{dockerRegistry}/{projectName}/ensembler-jobs/{ensemblerName}:{runID}

[leonlnj]

thanks!