fix: #94249 enhance persistent menu handling and maintain text selectio…

[vj-venkatesan]

Success criteria

Please describe what should be possible after this change. List all individual items on a separate line.

• The main text area focus must be preserved when toggling persistent menu
• The main text area focus must be preserved when interacting with the persistent menu

How to test

Please describe the individual steps on how a peer can test your change.

1. Go to an endpoint with persistent menu enabled
2. Use the following settings to enable persistent menu

3.  persistentMenu: {
      "menuItems": [
        {
          "title": "hello",
          "payload": "seess"
        }
      ],
      "title": "hello"
    }}

4. Open webchat
5. Type a message
6. Open Persistent menu
7. Close/Select an item
8. Observe the focus is retained at the correct position instead of jumping to the start of the text

Security

• Possible injection vector
• Authentication/Access controls touched
• Sensitive Data could be exposed
• XSS
• Logging/Monitoring touched
• Exchanges data with external systems
• No security implications

Additional considerations

• This PR might have performance implications

Documentation Considerations

These are hints for the documentation team to help write the docs.

[sushmi21]

Out of scope of this PR: I noticed that the persistent menu button is missing a visible focus indicator. Would be nice if it is handled

[vj-venkatesan]

Out of scope of this PR: I noticed that the persistent menu button is missing a visible focus indicator. Would be nice if it is handled

How about I open another PR quickly for that ?