[iOS] Flyout Menu CollectionView First Item Misaligned - fix

[kubaflo]

REVERTED

Description of Change

The regression is caused by this PR: #28670, but I think that the changes introduced by @albyrock87 let us simplify the code and easily fix the regression

Issues Fixed

Fixes #30483

Before	After
Screen.Recording.2025-07-09.at.02.08.10.mov	Screen.Recording.2025-07-09.at.02.07.27.mov

[dotnet-policy-service]

Hey there @@kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[Copilot]

Pull Request Overview

This PR fixes the misalignment of the first item in the iOS Shell flyout by removing the legacy SetHeaderContentInset logic and consolidating header offset calculations.

• Remove all calls to SetHeaderContentInset and delete the method implementation
• Simplify header offset logic in LayoutContent to always use the header’s frame height
• Drop obsolete call in ViewSafeAreaInsetsDidChange

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellTableViewController.cs	Removed the SetHeaderContentInset call in safe-area changes
src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellFlyoutLayoutManager.cs	Deleted SetHeaderContentInset method and calls; simplified the header offset logic

Comments suppressed due to low confidence (2)

src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellFlyoutLayoutManager.cs:191

• This layout change affects the iOS flyout header and first-item alignment; consider adding corresponding UI tests in TestCases.HostApp and TestCases.Shared.Tests to verify correct positioning under both scrollable and non-scrollable scenarios.

		internal void UpdateHeaderSize()

src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellFlyoutLayoutManager.cs:289

• By removing the conditional branch for ScrollView, the offset now always uses the header height instead of margin for scrollable content. Please verify that this doesn't reintroduce layout issues in scrollable scenarios, or restore a margin-based offset path if needed.

				contentYOffset += HeaderView.Frame.Height;

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[PureWeen]

/rebase

[albyrock87]

Thanks @kubaflo, this makes sense!
So I guess it means that the flyout UITest did not include VerifyScreenshot.

[PureWeen]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[PureWeen]

@kubaflo can you add a test for this?

[kubaflo]

I've added a test

[PureWeen]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).