My Site Dashboard: keep collection view position after an update

[leandroalonso]

Fixes #18195

This PR is somewhat a workaround around the collection view scrolling to the top after an update. In order to properly fix we'll need to review the way we display posts cards.

However, it does offer a better experience. :)

Simulator.Screen.Recording.-.iPhone.13.-.2022-03-30.at.14.45.55.mp4

To test

1. Run the app
2. Go to a site with Quick Start enabled and a few draft posts (enough content to scroll down as the video above)
3. Create a scheduled post
4. Check that the dashboard update but the position is the same

Regression Notes

1. Potential unintended areas of impact
   iPad

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   I manually tested on iPad.

3. What automated tests I added (or what prevented me from doing so)
   n/a

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

You can test the changes in Jetpack from this Pull Request by:

• Clicking here or scanning the QR code below
• Then installing the build number pr18245-4d64eb9 from App Center on your iPhone

The .ipa file can also be downloaded directly here.
If you need access to App Center, please ask a maintainer to add you.

[wpmobilebot]

You can test the changes in WordPress from this Pull Request by:

• Clicking here or scanning the QR code below
• Then installing the build number pr18245-4d64eb9 from App Center on your iPhone

The .ipa file can also be downloaded directly here.
If you need access to App Center, please ask a maintainer to add you.