Avoid usage of toBeTruthy/toBeFalsy in `ee/spec/frontend`

What does this MR do and why?

Related to &8422 (closed)

We want to set eslint rule to prevent usage of toBeTruthy and toBeFalsy as set in frontend testing guide for https://docs.gitlab.com/ee/development/testing_guide/frontend_testing.html#avoid-using-tobetruthy-or-tobefalsy

Before applying this rule we have to fix existing usages of toBeTruthy/toBeFalsy in our tests

This MR fixes files:

• ee/spec/frontend/epic/components/epic_form_spec.js
• ee/spec/frontend/geo_node_form/components/geo_node_form_selective_sync_spec.js
• ee/spec/frontend/geo_node_form/components/geo_node_form_spec.js
• ee/spec/frontend/geo_settings/components/geo_settings_form_spec.js
• ee/spec/frontend/oncall_schedule/add_edit_schedule_form_spec.js
• ee/spec/frontend/related_items_tree/components/create_epic_form_spec.js
• ee/spec/frontend/requirements/components/requirement_form_spec.js
• ee/spec/frontend/roadmap/components/preset_quarters/quarters_header_item_spec.js
• ee/spec/frontend/security_configuration/api_fuzzing/utils_spec.js
• ee/spec/frontend/security_configuration/dast_profiles/dast_profiles_sidebar/dast_profiles_sidebar_spec.js
• ee/spec/frontend/security_dashboard/components/instance/project_manager_spec.js
• ee/spec/frontend/security_dashboard/components/pipeline/security_dashboard_table_spec.js
• ee/spec/frontend/security_dashboard/components/shared/vulnerabilities_over_time_chart_buttons_spec.js
• ee/spec/frontend/security_dashboard/store/modules/vulnerabilities/mutations_spec.js
• ee/spec/frontend/usage_quotas/storage/components/namespace_storage_app_spec.js
• ee/spec/frontend/vue_shared/purchase_flow/components/step_spec.js
• ee/spec/frontend/vue_shared/security_reports/components/dismissal_comment_box_spec.js
• ee/spec/frontend/vue_shared/security_reports/components/modal_footer_spec.js
• ee/spec/frontend/vulnerabilities/header_spec.js
• ee/spec/frontend/vulnerabilities/vulnerability_training_spec.js

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