Move ScrollIntoView into ItemsControl.

[grokys]

What does the pull request do?

As described in #14524, ScrollIntoView is useful in ItemsControl in general and shouldn't be only available in SelectingItemsControl and derived.

Moving a method to a base class isn't a breaking change according to the MS docs so this should be OK.

✔️ ALLOWED: Moving a member into a class higher in the hierarchy than the type from which it was removed

Fixed issues

Fixes #14524

[grokys]

Not sure if this should be a backport candidate or not? On the one hand it's a simple change, on the other hand I kinda feel like it might be a breaking change in some way, even if the MS docs say it's not...

[avaloniaui-bot]

You can test this PR using the following package version. 11.1.999-cibuild0044625-beta. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[thevortexcloud]

On the one hand it's a simple change, on the other hand I kinda feel like it might be a breaking change in some way,

I can't see how unless there is some weirdness with some of the existing controls suddenly changing scroll position. There should be no existing dependencies on the functionality on any of the controls using the newly gained functionality. But I imagine you would have a better idea than me about how all the pieces interact with each other.