Broken link in accessibility docs

[swendlandt]

Issue Description

In https://sap.github.io/ui5-webcomponents/playground/?path=/docs/docs-advanced-accessibility--docs#invisible-messaging there is a link to Dynamic MessageStrip Generator Sample which does not work anymore.

Issue Type

• [ ] Documentation is unclear
• [x] Documentation is incorrect
• [ ] Documentation is missing
• [ ] Other

[IlianaB]

Hello @ui5-webcomponents-topic-p , I am forwarding this issue to you, because the link for Dynamic MessageStrip Generator Sample in Accessibility Docs is broken.