Update System.Text.Json in Controls.Media package

Author: michael-hawker

Microsoft.Toolkit.Uwp.UI.Controls.Media/Microsoft.Toolkit.Uwp.UI.Controls.Media.csproj

@@ -24,7 +24,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.UI.Xaml" Version="2.5.0" />
-    <PackageReference Include="System.Text.Json" Version="4.7.2" />
+    <PackageReference Include="System.Text.Json" Version="5.0.2" />
     <PackageReference Include="Win2D.uwp" Version="1.25.0" />
   </ItemGroup>