Update test dependencies and copilot icon

Updated TinyShop.Tests.csproj to use the latest versions of test dependencies (coverlet.collector, Microsoft.NET.Test.Sdk, MSTest). Added PrivateAssets and IncludeAssets to coverlet.collector for better package management. Updated 0-copilot-icon.png with a new version.

Author: jamesmontemagno

lab/images/0-copilot-icon.png

@@ -9,10 +9,13 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="coverlet.collector" Version="6.0.2" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="3.6.3" />
-    <PackageReference Include="MSTest.TestFramework" Version="3.6.3" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="4.0.2" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.0.2" />
   </ItemGroup>
 
   <ItemGroup>