[Target 4.10.1] Fix first delay of activity

[compulim]

Fixes #3431

Changelog Entry

Fixed

• Fixes #3431. Removed delay of first activity with replyToId pointing to a missing activity, by @compulim in PR #XXX

Description

When the first activity arrives, it always comes with a random replyToId, despite it is not actually replying to any conversation. This is a limitation of the design of SDK.

To mitigate the issue, Web Chat cannot delay the first (group of) activities even though the replyToId property is pointing to a potentially-transmitting activity.

Design

Please see the updated ACCESSIBILITY.md for details.

Specific Changes

• Updated queueIncomingActivitySaga not to hold the activity if one of the following is true:
  • If it is the first activity in the transcript
  • If another activity waiting for the same replyToId is already rendered

• 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
• Tests reviewed (coverage, legitimacy)

[corinagum]

Approved, pending a couple comments.