Add EnsureOutputFolder method and integrate it into EnsureCsProjFile

Added a new private method `EnsureOutputFolder` that checks if the
output folder specified by `AxSharpProject.OutputFolder` exists, and
if not, creates it. This method then returns the path to the output
folder.

Modified the `EnsureCsProjFile` method to call the newly added
`EnsureOutputFolder` method. This ensures that the output folder is
created before proceeding with the rest of the method's logic,
preventing potential errors related to missing directories.

src/AXSharp.compiler/src/AXSharp.Cs.Compiler/CsProject.cs

@@ -83,10 +83,21 @@ private static string GetExecutingAssemblyPath()
     }
 
 
+    private string EnsureOutputFolder()
+    {
+        if (!Directory.Exists(AxSharpProject.OutputFolder))
+        {
+            Directory.CreateDirectory(AxSharpProject.OutputFolder);
+        }
+
+        return AxSharpProject.OutputFolder;
+    }
+
     private void EnsureCsProjFile()
     {
         if (AxSharpProject.AxProject.ProjectInfo.Name != null)
         {
+            EnsureOutputFolder();
             string expectedCsProjFileFullPath = string.Empty;
             string expectedCsProjFile = string.Empty;
             if (string.IsNullOrEmpty(this.AxSharpProject.CompilerOptions?.ProjectFile))