Rework the "import a template" pop-in to match the mockups

## Resources:



![Image](https://github.com/ditrit/leto-modelizer/assets/82414381/3ab106f7-4fd6-4fb1-9ebd-ff0bc2f0090d)



![Image](https://github.com/ditrit/leto-modelizer/assets/82414381/3f9eba78-8be0-48b8-834f-8f0690787e0c)



