Connect negative results (defects, support costs, tech debt) to value stream

• https://gitlab.com/gitlab-org/gitlab-ee/issues/6283 measures positive benefits in the value stream.
• In addition to time and resource capacity spent (which is a cost), there may be negative results. This can be defects creating additional work for developers. This can be poorly designed features that incur additional support tickets.
• For example, even though https://gitlab.com/gitlab-org/gitlab-ee/issues/6283 may tell us that sign ups increased by 100%, it can be at the cost of 300% increase in support tickets. This cost needs to be combined and connected to the value stream.