Remove MAUI reference in readme

[ThomasNieto]

Prerequisites

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Steps to reproduce

Per #101 (comment) the following statement should be removed from the readme.

Note: A module named Microsoft.PowerShell.GraphicalTools used to be built and published out of this repo, but per #101 it is deprecated and unmaintained until such time that it can be rewritten on top of .NET MAUI.

Expected behavior

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Actual behavior

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Error details

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Environment data

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