Add module with source code: Delete "app" folder after download

resolves https://github.com/abpframework/abp/issues/3159

framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/ProjectModification/SolutionModuleAdder.cs

@@ -107,14 +107,18 @@ namespace Volo.Abp.Cli.ProjectModification
 
         private async Task DownloadSourceCodesToSolutionFolder(ModuleWithMastersInfo module, string modulesFolderInSolution, string version = null)
         {
+            var targetModuleFolder = Path.Combine(modulesFolderInSolution, module.Name);
+
             await SourceCodeDownloadService.DownloadAsync(
                 module.Name,
-                Path.Combine(modulesFolderInSolution, module.Name),
+                targetModuleFolder,
                 version,
                 null,
                 null
             );
 
+            await DeleteAppFolderAsync(targetModuleFolder);
+
             if (module.MasterModuleInfos == null)
             {
                 return;
@@ -126,6 +130,15 @@ namespace Volo.Abp.Cli.ProjectModification
             }
         }
 
+        private async Task DeleteAppFolderAsync(string targetModuleFolder)
+        {
+            var appFolder = Path.Combine(targetModuleFolder, "app");
+            if (Directory.Exists(appFolder))
+            {
+                Directory.Delete(appFolder, true);
+            }
+        }
+
         private async Task AddNugetAndNpmReferences(ModuleWithMastersInfo module, string[] projectFiles)
         {
             foreach (var nugetPackage in module.NugetPackages)