Bug: MinRedundancyMaxRelevance Function Modifies Input DataFrame by Adding target Column

[Pacman1984]

Description

The MinRedundancyMaxRelevancy class adds the target column to X.

Steps to Reproduce

1. Import the MinRedundancyMaxRelevancy class
2. Create a DataFrame X and a target series y.
3. Call the MinRedundancyMaxRelevancy fit function with X and y as inputs.
4. Observe that the target column is unexpectedly added to DataFrame X.

Expected Behavior

The ``MinRedundancyMaxRelevancyfit method should compute the necessary values and return them without modifying the input DataFrameX`.

Actual Behavior

The input DataFrame X is being modified by having the target column appended to it after calling MinRedundancyMaxRelevancy fit method.

[Pacman1984]

This is not happening with a custom relevance_func and redundancy_func setup

[ThomasBury]

Good catch, I added the missing copy() to prevent modifying the input pandas DF when fitting the selector