Try to resolve image paths by replacing backslashes or forward slashes in EmbedTexturesProcess (#5844)

* Try to resolve image paths by replacing backslashes.

* Some changes suggested by CI

* Removed usage of <filesystem>.

* Removing usage of C++20/C++23 features

---------

Co-authored-by: Kim Kulling <kimkulling@users.noreply.github.com>

code/PostProcessing/EmbedTexturesProcess.h

@@ -77,6 +77,8 @@ public:
     virtual void Execute(aiScene* pScene) override;
 
 private:
+    // Try several ways to attempt to resolve the image path
+    std::string tryToFindValidPath(const std::string &imagePath) const;
     // Resolve the path and add the file content to the scene as a texture.
     bool addTexture(aiScene *pScene, const std::string &path) const;