docs(accessibility): add interactive modal accessibility diagnostic exercise (#42851) - #42869

Changed pages include:

• index.html - view
• 404.html - view
• about/index.html - view
• components/index.html - view
• docs/index.html - view
• docsref/index.html - view
• examples/index.html - view
• getting-started/index.html - view
• migration/index.html - view
• docs/5.3/index.html - view

There are more changes not included in the list