Dynamic Profile Generator for Windows PowerShell

Description of the new feature/enhancement

It'd be nice if the "Windows PowerShell" profile worked like the other profiles, and could be disabled using disabledProfileSources.

This would remove the need to carry a 'hidden' overriding profile per #5459, as disabledProfileSources made possible for the other profile sources.

Proposed technical implementation details (optional)

I guess it just needs new IDynamicProfileGenerator implementation, that replaces (and slurps up?) the existing Windows PowerShell profile if present, which appears to have a fixed GUID ({61c54bbd-c2c6-5271-96e7-009a87ff44bf}), fix the 'pick a default profile' logic, and then remove it from the defaults.json.

If the same thing is done for CMD, then I guess the risk appears of how to handle the case that there are no profiles available, where right now I guess you always have those two profiles, even if somehow they are not usable.

Start by tracing existing IDynamicProfileGenerator implementations and the Windows PowerShell profile entry in defaults.json, including its fixed GUID. Verify how disabledProfileSources and default-profile selection currently handle the profile. Done means Windows PowerShell can be disabled through disabledProfileSources without a hidden override, while the default profile behavior remains valid.