Add checkbox to GKE publish dialog to update deployment with the same name if exists.

[ivannaranjo]

Having a checkbox in the GKE publish dialog will allow the user to pre-choose whether to update the existing deployment with the same name when starting the publish process. The current process can get confusing because it takes a while to detect whether an existing deployment with that name already exists. If the user pre-approved this then we can go ahead with the publishing process.

If the user doesn't pre approve then we need to ask the user anyway, or fail if an existing deployment with that name exists.

[ILMTitan]

I don't think a checkbox is the best solution here. I think an editable combo box, so the user can see the existing deployments, combined with a text block that tells the whether they are creating or updating would be sufficient.