Read Adaptive Card text in the live region when the card has no speak

[Eugene (OEvgeny)]

Adaptive Cards without speak are announced as just "A card:" when they arrive.

Changelog Entry

Fixed

• Fixed screen readers announcing Adaptive Cards without speak as just "A card", they now read the card text, in PR #5922, by @OEvgeny

Description

The live region copy of an Adaptive Card only used speak, so cards without it (most bots) were announced as "A card:" with none of their text. Without speak, it now reads the visible card text in document order (hidden elements, including hidden inputs, and collapsed Action.ShowCard cards are skipped); speak still wins when present.

Design

• Text comes from TextBlock, RichTextBlock, FactSet ("title: value") and Image alt text of visible elements only, as written: Markdown and {{DATE()}} are not processed, like hero card text.
• Overlaps Name and pre-fill Adaptive Card inputs in the live region as in the card #5913 in AdaptiveCardAttachment.js (label vs. inputs); the two merge cleanly.

Specific Changes

• AdaptiveCardAttachment.js: card label falls back to the card text when speak is missing; walkAllItems skips hidden elements

• adaptiveCard.text.html: snapshot 1, the live region reads "A card: Seattle Sunny, 21°C Bot avatar Humidity: 40% Wind: 8 km/h Updated 5 minutes ago"

• adaptiveCard.hiddenText.html: snapshot 1, hidden text, a hidden input and the collapsed show-card text are not read ("A card: Seattle")

• adaptiveCard.speakOverText.html: snapshot 1, a card with speak is still read by speak only

• CHANGELOG.md: entry

• I have added tests and executed them locally

• I have updated CHANGELOG.md

• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)

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[Eugene (OEvgeny)]

Might be too naive, but maybe worth it as a start, William Wong (@compulim) ?