Reduce the duplicate logic when gdk update is run

Overview

Currently there's duplicated logic that's run as part of a gdk update as we essentially run a gdk reconfigure at the very end. Known duplicate logic:

• Updating gitlab-org/gitlab
• Updating gitlab-org/gitaly to <SHA>
• Successfully fetched and checked out '<SHA>' for 'gitaly/'
• Building gitlab-org/gitaly <SHA>

Impacted categories

The following categories relate to this issue:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Proposal

⚠ This issue needs #1699 (closed) investigated first.

Refine the logic that's executed when gdk update is called to only call the necessary logic. A proposed plan might be:

• Take note of all the tasks that a gdk update executes
• Take note of all the tasks that a gdk reconfigure executes
• Update gdk update command to only execute unique steps
• Update gdk reconfigure command to only execute unique steps