Hiding dashboard cards: fix scroll position

[kean]

Related issue: #20296

Fixes an issue with an incorrect scroll position after hiding multiple cards in the Personalize Home Tab screen and then turning them back on. The issue was reported by @guarani here (see the linked comment for the video).

To test:

• Open Jetpack and enable the "Personalize Home Tab" flag
• Tap "Personalize Home Tab" on the bottom of the site's Dashboard
• Turn all cards off, then turn some of them back off
• Go back the Dashboard
• Verify that the scroll view has normal scroll position: cards are visible

Regression Notes

1. Potential unintended areas of impact.
   Site Dashboard.
2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Manual testing
3. What automated tests I added (or what prevented me from doing so)
   No

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.

[kean]

The scroll(_:to:) code was added in the following PR as a workaround. Unfortunately, it breaks the new personalization feature (see the comment).

I tried removing the workaround to see if it's still needed and was not able to reproduce the issue it's supposed to be fixing, so it should be good to merge.

[momo-ozawa]

Works as described! I kicked off a CI build - if it's green all good to merge 👍