Polish infrastructure merge review notes

Author: sfmskywalker

src/Elsa.PackageManifest.Generator.Core/Generation/ManifestMetadataMerger.cs

@@ -96,7 +96,7 @@ private static IReadOnlyList<ManifestInfrastructureRequirementReference> MergeIn
         IReadOnlyList<ManifestInfrastructureRequirementReference> first,
         IReadOnlyList<InfrastructureRequirementOverride>? second)
     {
-        if (second is null)
+        if (second is null || second.Count == 0)
             return first;
 
         var result = first.ToList();

tests/Elsa.PackageManifest.Generator.Testing/CShellsFeatureFixtures.cs

@@ -85,7 +85,7 @@ internal sealed class ManifestExtensionAttribute(string key, string value) : Att
     public string Value { get; } = value;
 }
 
-[AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
+[AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = false)]
 internal sealed class ManifestInfrastructureAttribute(string id, string kind) : Attribute
 {
     public string Id { get; } = id;