Update to 'latest' nuget package

see gui-cs/Terminal.Gui#3779

Author: tznind

Showcase/Showcase.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Terminal.Gui" Version="2.0.0-develop.4373" />
+    <PackageReference Include="Terminal.Gui" Version="2.0.0-develop.1616" />
   </ItemGroup>
 
 </Project>

src/TerminalGuiDesigner.csproj

@@ -151,7 +151,7 @@
 		<PackageReference Include="Serilog" Version="4.2.0" />
 		<PackageReference Include="Serilog.Extensions.Logging" Version="9.0.0" />
 		<PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
-		<PackageReference Include="Terminal.Gui" Version="2.0.0-develop.4373" />
+		<PackageReference Include="Terminal.Gui" Version="2.0.0-develop.1616" />
 		<PackageReference Include="nlog" Version="5.3.3" />
 		<PackageReference Include="Basic.Reference.Assemblies.Net80" Version="1.7.7" />
 		<PackageReference Include="System.CodeDom" Version="8.0.0" />