[Backport 2.0.x] Datahub (fix): Handle UpdateFrequency not defined

[jahow]

Backport of #693

[github-actions]

Affected libs: api-metadata-converter, feature-search, feature-record, feature-router, feature-map, feature-dataviz, api-repository, feature-catalog, feature-auth, feature-editor, ui-search, ui-elements, ui-catalog, util-shared, ui-widgets, ui-inputs, data-access-datafeeder, util-data-fetcher, util-app-config, common-fixtures, ui-map, data-access-gn4, common-domain, ui-dataviz, ui-layout, util-i18n,
Affected apps: metadata-converter, metadata-editor, datahub, demo, webcomponents, search, map-viewer, datafeeder, data-platform,

• 🚀 Build and deploy storybook and demo on GitHub Pages
• 📦 Build and push affected docker images

[coveralls]

coverage: 82.852% (-1.1%) from 83.952%
when pulling 0978e4b on backport/693-to-2.0.x
into 9d30a1b on 2.0.x.