Honor explicitly requested package identifier during uninstall

[JanKrivanek]

Problem

Fixes #4156
Remote feed packages could not be unistalled when unistall command run from local folder with subfolder of clashing name

Solution

The package identifier requested to be unistalled is checked first as is only then expanded for wildcards or local folders. If any package found - it's uninstalled and no error is logged

Checks:

• Added unit tests
• Added #nullable enable to all the modified files ?

[vlada-shubina]

not actionable:

just to restate dislike for current ExpandMaskedPath logic.
I feel like path expansion should be done much later likely after it is determined that the package is folder.

[vlada-shubina]

Looks good, only small concern that likely DetermineSourcesToUninstallAsync needs better modularization now (likely needed before).