[VSA] Usability improvements
## Overview VSA's original approach and design are good, but over the years the core capabilities have shifted away from their main purpose, making them unusable for solving key VSM problems. A few examples are: [no actionable insights from VSA](https://gitlab.com/gitlab-org/gitlab/-/issues/366729), [chart displays confusing data](https://gitlab.com/groups/gitlab-org/-/epics/8374), [no possibility to persist filters](https://gitlab.com/groups/gitlab-org/-/epics/7412) and [flawed metric data](https://gitlab.com/gitlab-org/gitlab/-/issues/381716). This epic to group some bight-sized usability improvements for VSA that we can pull into milestones when we have capacity. This is a collection of improvements to the existing UI rather than larger feature development work.
epic