Add derivative(t) method to BezierCurve class

[nsree0507]

Describe your change:

• Add an algorithm?
  Added a derivative(t) method to the BezierCurve class to compute the tangent vector at any point t on the curve. This supports curves of any degree and is useful for animation, motion planning, and curve analysis.

Fixes #13861

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.
• This pull request resolves issue number: Fixes graphics/bezier_curve.py: tangent direction and derivative of the curve #13861

[cclauss]

Closing "tests are failing" PRs to prepare for Hacktoberfest