Refactor code in numerical methods notebooks

- Updated import order in Point_Fixe.ipynb for consistency.
- Changed lambda functions to regular function definitions for clarity in Point_Fixe.ipynb.
- Added numpy import in TP1_EDO_EulerExp.ipynb, TP2_Lokta_Volterra.ipynb, and TP3_Convergence.ipynb for better readability.
- Modified for loops in TP1_EDO_EulerExp.ipynb and TP2_Lokta_Volterra.ipynb to include strict=False for compatibility with future Python versions.

M1/Statistical Learning/TP0_Intro_Jupyter_Python.ipynb

@@ -259,7 +259,7 @@
     "import numpy as np\n",
     "\n",
     "# Import  part of a  library\n",
-    "from scipy.stats import norm, multivariate_normal"
+    "from scipy.stats import multivariate_normal, norm"
    ]
   },
   {