Added RMSE loss function fixes- #13379

[TASMAYU]

Describing the changes made:
I'm adding the RMSE (Root Mean Squared Error) loss function to the machine_learning module as we know it's a commonly used regression loss function .

Checklist:

I have read CONTRIBUTING.md.
This pull request is all my own work
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.

Reference:

RMSE: https://en.wikipedia.org/wiki/Root-mean-square_deviation
( Get through the foundational understanding of the RMSE through it as such we already know as well about the RMSE but for sources referring this )

Fixes #13379