Add missing ~/flash import

Several files are missing ~/flash import resulting in failing several tests when being run separately:

• spec/javascripts/vue_mr_widget/components/states/mr_widget_wip_spec.js

See #67206 (moved) for details

Does this MR meet the acceptance criteria?

Conformity

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• [-] Documentation created/updated or follow-up review issue created
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• [-] Separation of EE specific content