Use -NoProfile for suggested powershell install command

[duckinator]

We should specify -NoProfile in the suggested powershell install command.

This was suggested in astral-sh/uv#10299, with the following explanation:

-NoProfile (appreviated to -NoP) is used as the profile can interfere with the intended operation

None of us are familiar enough with PowerShell to know if there's any problems with using it, so we should look into it and if everything looks good start using it.

(NOTE: We've decided to explicitly not use abbreviated flags for PowerShell commands.)

[duckinator]

Digging into this a bit more, I think we want this.

I'm basing this opinion on:

• PowerShell documentation
• further explanation in that original uv PR: e.g., profiles could remove aliases (like irm)

Updating the issue accordingly.