[Compilation fix][Inflight] Fix PublicAPI.Unshipped.txt duplicate entries and missing MEM0002 suppressions in inflight/Current

[NafeelaNazhir]

Description:

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Description

#36312 enabled the MemoryAnalyzers Roslyn analyzer at error severity for Controls.Core
on iOS/MacCatalyst (MEM0001–MEM0003: retained events, retain-cycle-prone strong references,
and non-deterministic event teardown). After that merge landed on inflight/current, the
build broke locally in two ways, both fixed here:

1. Duplicate PublicAPI.Unshipped.txt entries (net-ios, net-maccatalyst) — 3 lines each
were duplicated: StructuredItemsViewController2<TItemsView>.UpdateFlowDirection(),
SwipeItems.OnPropertyChanged(string), Label.~Label(). Removed the extra copies.

2. Missing MEM0002 suppressions on fields that are already cleared in their component's
teardown path but weren't annotated:

• NavigationRenderer: _largeTitleProxyScrollView, _largeTitleObservedScrollView, _largeTitleContentOffsetObserver
• UIContainerCell: _viewResource
• MauiCollectionView: _contentOffsetObserver

Added justified [UnconditionalSuppressMessage("Memory", "MEM0002", ...)] attributes citing
each field's actual disposal path.

No functional/runtime behavior change — purely restores the intended state of #36312.

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

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

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
There may be pipelines that require an authorized user to comment /azp run to run.