RichText: remove iOS scroll adjusting

[ellatrix]

Description

With our new smooth enter behaviour (#11287), we no longer have a focus delay when creating a new paragraph on enter. It seems that we can remove the iOS fixes that adjust the scroll position when a block receives focus and when enter/delete is pressed.

Removing the fix actually results in even nicer scrolling because it is handled natively.

Reverts #5769.

How has this been tested?

Test scroll behaviour on iOS when pressing enter and backspace.

Screenshots

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.

[jasmussen]

Wow. This is hardcore impressive refactorings you've been doing. I love the amount of red in this PR! And the experience seems great to me:

I think it's important we get a few more people testing this as a sanity check, remember it has to be a physical device, or the Xcode simulator. But first impression looks seriously promising. 👏👏👏👏👏

One issue that is completely unrelated, but becomes apparent again when testing this: we probably should never invoke "isEditing" mode on mobile, and always show the toolbar and selection borders. Reason being that it's otherwise both difficult and unintuitive to figure out how to make text bold. We are a bit limited here in what we can do because we are not a native app, and we are at the mercy of Mobile Safari (see also this) — but it still seems a better experience. But again, that's unrelated to this PR.

REALLY nice work!

[jasmussen]

Notably I'm super duper thrilled to see that the jumping toolbar is gone from this branch 💥

[ellatrix]

I have the same result as you shared in the video on a physical device. :)

[gziolo]

Code removal looks legit 👍 I haven't tested but I trust you two :)

[ellatrix]

Tested it also on a different device. Thanks!

[mcsf]

So glad to see this code go. :)