Replace instances of `loading-button` with `gl-button`

Replace all instances of loading-button, which lives in vue_shared with gl-button, which has a loading prop.

Dependency: gitlab-ui!1102 (merged) needs to be merged.

This component needs to be replaced in the following places:

• app/assets/javascripts/badges/components/badge_form.vue
• app/assets/javascripts/clusters/components/application_row.vue
• app/assets/javascripts/clusters/components/ingress_modsecurity_settings.vue
• app/assets/javascripts/clusters/components/knative_domain_editor.vue
• app/assets/javascripts/clusters/components/uninstall_application_button.vue
• app/assets/javascripts/create_cluster/eks_cluster/components/eks_cluster_configuration_form.vue
• app/assets/javascripts/create_cluster/eks_cluster/components/service_credentials_form.vue
• app/assets/javascripts/environments/components/environment_stop.vue
• app/assets/javascripts/error_tracking/components/error_details.vue
• app/assets/javascripts/error_tracking_settings/components/error_tracking_form.vue
• app/assets/javascripts/ide/components/commit_sidebar/form.vue
• app/assets/javascripts/import_projects/components/import_projects_table.vue
• app/assets/javascripts/notes/components/comment_form.vue
• app/assets/javascripts/pipelines/components/header_component.vue
• app/assets/javascripts/pipelines/components/nav_controls.vue
• app/assets/javascripts/pipelines/components/pipelines_table_row.vue
• app/assets/javascripts/vue_merge_request_widget/components/deployment/deployment_stop_button.vue
• ee/app/assets/javascripts/batch_comments/components/draft_note.vue
• ee/app/assets/javascripts/batch_comments/components/publish_button.vue
• ee/app/assets/javascripts/batch_comments/components/review_bar.vue
• ee/app/assets/javascripts/epic/components/epic_create.vue
• ee/app/assets/javascripts/epic/components/epic_header.vue
• ee/app/assets/javascripts/security_dashboard/components/vulnerability_action_buttons.vue
• ee/app/assets/javascripts/vue_shared/security_reports/components/dismiss_button.vue
• ee/app/assets/javascripts/vue_shared/security_reports/components/dismissal_comment_modal_footer.vue
• ee/app/assets/javascripts/vue_shared/security_reports/components/dismissal_note.vue
• ee/app/assets/javascripts/vue_shared/security_reports/components/modal_footer.vue
• ee/spec/frontend/epic/components/epic_header_spec.js
• spec/frontend/import_projects/components/import_projects_table_spec.js
• spec/frontend/notes/components/comment_form_spec.js

Once the above is done, remove:

• app/assets/javascripts/vue_shared/components/loading_button.vue
• spec/frontend/vue_shared/components/loading_button_spec.js