Add DP MatchSizeWith to PackIcon

[corvinsz]

Possibly fixes #1216

This adds a new dependency property MatchSizeWith to the PackIcon, so the icon can be linked to another FrameworkElement to automatically adapt it's height. This is useful to automatically size an icon which belongs to some text.
As @Keboo mentioned in the linked issue, there are some trade-offs to be made, which I don't think we can fully eliminate.

See MD spec here: https://m3.material.io/styles/icons/applying-icons (Using Material Symbols with typography)

The icons Height and Width are bound to the referenced FrameworkElement's ActualHeight to keep it rectangular.

Example usage:

<StackPanel Orientation="Horizontal">
  <materialDesign:PackIcon Kind="Person"
                           MatchSizeWith="{Binding ElementName=tbTitle}" />
  <TextBlock x:Name="tbTitle"
             Style="{StaticResource MaterialDesignHeadline2TextBlock}"
             Text="Edit Person" />
</StackPanel>

If we actually want something like this, and it merges, I will add a follow-up PR for more documentation (incl. MD3 example).

[mzy666888]

good work

[Keboo]

I like the change but perhaps a different name for the DP. Thoughts on ScaleToSizeOf?

[corvinsz]

Sounds good. I renamed the property from MatchSizeWith to ScaleToSizeOf and also adjusted the tests name.