Use injection over prop injection

What does this MR do?

This is a simple follow up from this discussion. Since groupFullPath and projectFullPath are both injected we moved the logic to compute the fullPath for the vulnerability_count_list component into the component itself. Previously it was in the parent component.

Screenshots (strongly suggested)

There are no visual changes.

Does this MR meet the acceptance criteria?

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Related to #328232 (closed)