Fix BindableObject.GetLocalValueEnumerator() removed by #33584 breaks VS Live Property Explorer

[devanathan-vaithiyanathan]

Issue details:

After PR #33584 (BindableObject property access micro-optimizations), Visual Studio's Live Property Explorer stops showing any property values for MAUI controls. The feature becomes completely blank.

Description of changes:

PR #33584 removed GetLocalValueEnumerator(), LocalValueEnumerator, and LocalValueEntry from BindableObject as "unused dead code" — a grep of the MAUI codebase confirmed zero internal callers. However, Visual Studio's Live Property Explorer calls GetLocalValueEnumerator() via reflection at runtime to enumerate locally-set bindable property values on live objects. With these types removed, the reflection call fails silently and the panel shows nothing.

This changes restores all three types, adapted to the new Dictionary<int, BindablePropertyContext> storage introduced by #33584 — the enumerator now iterates .Values (the BindablePropertyContext objects directly) and reads context.Property to expose the BindableProperty, since the dictionary key is now an int rather than the property itself.

Tested the behavior in the following platforms.

• Android
• Windows
• iOS
• Mac

Before	After
Windows Before.mp4	Windows After.mp4

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 36063

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 36063"

[sheiksyedm]

@kubaflo This PR addresses the regression caused by PR #33584, which has already been included in the main branch. The fix is straightforward, as it restores code that was previously removed from PR #33584 because it appeared to be unused, but is actually accessed through reflection.

Therefore, this PR can be merged directly into the main branch instead of going through the inflight branch.