Portable uninstall should check target path of symlink before removal

[ryfu-msft]

Brief description of your issue

Currently, Portable uninstall only checks that the portable symlink path matches what is recorded in ARP. However, the symlink could be modified to point to a different target exe. We should verify that the target of the symlink points to the correct portable exe that we placed down during installation.

Steps to reproduce

Modify symlink to point to another exe. Uninstall will still remove the symlink even though it is modified.

Expected behavior

Symlink should not be removed as it has been modified by the user.

Actual behavior

If the symlink path matches the symlink path recorded in ARP, the symlink will always be removed regardless of whether it has been modified by the user.

Environment

Windows Package Manager 1.3.1391-preview