[Windows] Fix for ListView ScrollTo Method throws NullReferenceException

[Tamilarasan-Paranthaman]

Root Cause of the issue

• The exception occurred because the scroll request was processed before the control was fully loaded, causing the dispatcher to be null.

Description of Change

• I resolved the issue by invoking the ScrollTo method within MainThread.BeginInvokeOnMainThread. This ensures that the scroll request is executed on the main thread.

Test Case

• The test case has already been added in the following PRs
• [Testing] Enabling ported UITests from Xamarin.UITests to Appium - 30 #26367 (Issue3788)
• [Testing] Enabling ported UITests from Xamarin.UITests to Appium - 29 #26365 (Bugzilla42956)

Reference

https://github.com/xamarin/Xamarin.Forms/blob/5.0.0/Xamarin.Forms.Platform.WPF/Renderers/ListViewRenderer.cs#L427

Issues Fixed

Fixes #26345

Tested the behaviour in the following platforms

• Android
• Windows
• iOS
• Mac

Screenshot

Before Issue Fix	After Issue Fix
WithException.mp4	FixVideoofListView.mp4

[Redth]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[rmarinho]

Can we rebase and reenable the tests from the other prs
https://github.com/dotnet/maui/pull/26367/files#diff-ddeee3ee10f01134abc383c69a74dc4a65b5e8cbfa6dd682ceeb34734c6bdd6bR1

[Tamilarasan-Paranthaman]

/rebase

[rmarinho]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[Tamilarasan-Paranthaman]

Can we rebase and reenable the tests from the other prs https://github.com/dotnet/maui/pull/26367/files#diff-ddeee3ee10f01134abc383c69a74dc4a65b5e8cbfa6dd682ceeb34734c6bdd6bR1

@rmarinho, I have reenabled the test cases.

Feedback addressed