[Datahub] : Handle erroneous api links

[cmoinier]

Description

This PR aims at displaying an error message in the API form when the link is erroneous/dead/not responding. It would also add a spinning loader for the delay during which the initial requests are made.

Screenshots

Quality Assurance Checklist

• Commit history is devoid of any merge commits and readable to facilitate reviews
• If new logic ⚙️ is introduced: unit tests were added
• If new user stories 🤏 are introduced: E2E tests were added
• If new UI components 🕹️ are introduced: corresponding stories in Storybook were created
• If breaking changes 🪚 are introduced: add the breaking change label
• If bugs 🐞 are fixed: add the backport <release branch> label
• The documentation website 📚 has received the love it deserves

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This work is sponsored by MEL.

[github-actions]

Affected libs: ui-elements, feature-notifications, feature-catalog, feature-record, feature-router, feature-editor, feature-search, feature-map, feature-dataviz, ui-catalog, ui-search,
Affected apps: metadata-editor, demo, datahub, webcomponents, map-viewer, search, datafeeder,

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

[coveralls]

coverage: 83.789% (-1.3%) from 85.088%
when pulling e902961 on add-error-message-api-form
into cec60ff on main.

[github-actions]

📷 Screenshots are here!

[jahow]

Currently on hold because of a temporary lack of resources

[CLAassistant]

All committers have signed the CLA.