Modify targeting (explicit / nonexplicit) for source [PowerShell]

### Relevant area(s)

WinGet CLI, PowerShell Module

### Description of the new feature / enhancement

I want to be able to modify the targeting for WinGet sources using the Microsoft.WinGet.Client PowerShell module.

Maybe a cmdlet like `Set-WinGetSourceTargeting` 

### Proposed technical implementation details

_No response_