Solve the problem with the original exclude file-mladvanced part

[Lola-jo]

前期在 md2ipynb 的过程中，有一些 notebook build 不通过，所以暂时放到了 config exclude 里面

现在 md2ipynb 收尾，那么就需要把这些 notebook 的 build 不通过的问题解决

• - 'ml-advanced/ensemble-learning/random-forest.ipynb'
• - 'ml-advanced/clustering/introduction-to-clustering.ipynb'
• - 'ml-advanced/clustering/k-means-clustering.ipynb'
• - 'ml-advanced/unsupervised-learning.ipynb'