Update simple_neural_network.py

[Manoj-Routhu]

Describe your change:

Fixes #9718
Optimized the code using Vectorization technique with list comprehension

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[cclauss]

As discussed in CONTRIBUTING.md please run the tests on your machine to ensure tests pass.
python3 -m doctest -v neural_network/simple_neural_network.py

We will also need a timeit benchmark to prove the performance claims.
Some sample benchmarks: https://github.com/search?q=repo%3ATheAlgorithms%2FPython%20timeit