Refactor to introduce nullable types and reduce compiler warnings (#801)

* Introduce nullable types to Core, Infrastructure and PublicApi projects

* Refactor unit tests

* Fixed failing tests

* Introduce Parameter object for CatalogItem update method

* Refactor CataloItemDetails param object

* Refactor following PR comments

src/PublicApi/CatalogItemEndpoints/UpdateCatalogItemEndpoint.cs

@@ -41,8 +41,9 @@ public class UpdateCatalogItemEndpoint : IEndpoint<IResult, UpdateCatalogItemReq
         var response = new UpdateCatalogItemResponse(request.CorrelationId());
 
         var existingItem = await _itemRepository.GetByIdAsync(request.Id);
-
-        existingItem.UpdateDetails(request.Name, request.Description, request.Price);
+        
+        CatalogItem.CatalogItemDetails details = new(request.Name, request.Description, request.Price);
+        existingItem.UpdateDetails(details);
         existingItem.UpdateBrand(request.CatalogBrandId);
         existingItem.UpdateType(request.CatalogTypeId);
 

src/PublicApi/PublicApi.csproj

@@ -6,6 +6,7 @@
     <UserSecretsId>5b662463-1efd-4bae-bde4-befe0be3e8ff</UserSecretsId>
     <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
     <DockerfileContext>..\..</DockerfileContext>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>