MM-24351 Update react virt list to be based on new library

[sudheerDev]

Summary

Updating react window to be based on new repo https://github.com/mattermost/dynamic-virtualized-list
This includes minor cleanup made for library API which reflects the changes made in the PR.

Ticket Link

https://mattermost.atlassian.net/browse/MM-24351

Note: testing will be a smoke testing scroll, loading posts, switching channels

[Willyfrog]

/update-branch

[hmhealey]

I'd be interested in learning more about the library at some point. Maybe a blog post or a demo of some sort? 🙂

[jgilliam17]

Adding testing steps, per discussion with Sudheer

This requires a smoke test around scroll conditions, including, but not limited to:

• loading more posts
• checking if landing on unread post works etc
• switching channel and coming back
• posting new post to keep at bottom

[jgilliam17]

Thank you @sudheerDev

1. I am not able to add new posts on any of the channels/DMs
   edited: Messages post, but remain out of view. Posts can be searched for and display on the RHS, emojis have strange background disregard that's just highlight

2. Also, text "Beginning of..." text is missing. See image.

3. Any attempt to resize browser window causes white screen

[stylianosrigas]

I had to remove the Setup Cloud Test Server label because we need to deprecate the cluster the installation is running. Reapplied successfully.

[sudheerDev]

/update-branch

[sudheerDev]

@jgilliam17 Can you test this again?

[jgilliam17]

/update-branch

[jgilliam17]

Thank you @sudheerDev
Tested, looks good to merge.

• Verified scrolling and loading more posts, including unreads, switching channels and user remaining at the bottom when adding new post.
  Thank you! @saturninoabril for running the E2Es here

[mm-cloud-bot]

Test server destroyed