Add the stub for tippy to the Throughput report tests

[tamararivera]

This should prevent some of the noise when running the component test for the Throughput report, as now we get a lot of warnings because this is missing.

Reviewer Checklist

• Components are broken down into sensible and maintainable sub-components.
• Styles are scoped to the component using it. If multiple components need to share CSS, then a .css file is created containing the shared CSS and imported into component scoped style sections.
• Naming is consistent with existing code, and adequately describes the component or function being introduced
• Only functions utilizing Vue state or lifecycle hooks are named as composables (i.e. starting with 'use');
• No module-level state is being introduced. If so, request the PR author to move the state to the corresponding Pinia store.

[ngallegos]

Should we add a global tippy stub so future tests don't have to add it?

This suggestion PR does that and removes test-specific stubs that generate duplicate warnings when the global stub is introduced:

• #3064