Update sample to echo typing as message

[compulim]

Related to #4031.

Changelog Entry

Samples

• Fixes #4031. Updated 05.custom-components/b.send-typing-indicator to reply with message activity, instead of typing activity, in PR #4063, by @compulim

Description

To reduce confusion, the sample is updated to echo back typing activity as a message, instead of a typing activity.

Design

Today, in this sample, when the end-user type, the bot will send a corresponding typing activity. As a result, a typing indicator GIF animation will be shown.

This behavior confuses accessibility audit team as the GIF animation is not desirable when the end-user type.

This PR will update the sample. The bot will send a message activity instead.

Specific Changes

• Updated sample 05.b to send echo-typing-as-message command, instead of echo-typing command

• 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)