[Webcomponents] : Display error message when record fails to load/not found

[cmoinier]

Description

This PR introduces an error message when the record fails to load/is not found in gn-record-view.

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

[github-actions]

Affected libs: api-repository, feature-catalog, feature-record, feature-router, feature-search, feature-map, feature-editor, feature-auth, ui-map, feature-dataviz,
Affected apps: geoadmin-demo, webcomponents, metadata-editor, datahub, demo, map-viewer, search, datafeeder,

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

[jahow]

thanks!