TRea - phase out selectors part 2

What does this MR do and why?

• Continue to phase out data-qa-selector in these places:
  • app/assets/javascripts/sidebar/components/labels/label_select_vue
  • app/assets/javascripts/super_sidebar/components
  • app/assets/javascripts/vue_shared/components
  • app/assets/javascripts/vue_shared/security_configuration/components
• As well as remove unused selectors along the way

Relates gitlab-org/quality/quality-engineering/team-tasks#1822 (closed)

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.