Add cast to ComAwareWeakReference rehydrate path

[jkotas]

Prevents hard to diagnose crashes caused by COM interop rehydrating wrong type.

[Copilot]

Pull Request Overview

This PR addresses COM interop type safety issues by adding explicit casting during the weak reference rehydration process. The changes prevent hard-to-diagnose crashes that can occur when COM interop rehydrates objects to the wrong type.

Key Changes:

• Modified the COM-aware weak reference rehydration path to include runtime type casting
• Refactored ComAwareWeakReference to expose the rehydration method with generic type parameter
• Updated both generic and non-generic WeakReference classes to use the new type-safe rehydration approach

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/libraries/System.Private.CoreLib/src/System/WeakReference.cs	Updated non-generic WeakReference to use new type-safe COM-aware rehydration with explicit object casting
src/libraries/System.Private.CoreLib/src/System/WeakReference.T.cs	Updated generic WeakReference to use new type-safe COM-aware rehydration with explicit T casting
src/libraries/System.Private.CoreLib/src/System/ComAwareWeakReference.cs	Refactored to expose generic RehydrateTarget method with runtime casting and consolidated access through GetFromTaggedReference

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[jkotas]

/backport to release/10.0

[github-actions]

Started backporting to release/10.0: https://github.com/dotnet/runtime/actions/runs/17267267126