#18425 modified the Coder UI & CLI to issue a stop build and then a start build when updating a workspace's template.

At time of writing the vs-code extension currently still maintains the previous behaviour of simply issuing a start build when a template is updated.

This speaks to the need for a logical "workspace template update" endpoint which handles the coordination of builds to achieve the outcome.

NOTE: the same is true for workspace restarts; the client has to coordinate the stop-then-start mechanics.