Added Kruskal's Algorithm in graph folder code in python

[Smriti-Prajapati]

Describe your change:

This code is used to find the shortest path to connect all points in a network. It's like finding the cheapest way to connect all cities in a country with roads. The code sorts all the possible roads by their cost, then chooses the cheapest ones that don't create a loop. It keeps doing this until all cities are connected.

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• 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]

Closing tests_are_failing PRs to prepare for Hacktoberfest