Fix code transform animation

[Mindev27]

Closed #4103

I added a new CodeTransform function. The current Transform with Code looked weird, but now it works much better.

The logic is as follows:

When applying CodeTransform from before_code to after_code:

• Split both before_code and after_code into lines and remove leading indentation.
• Use a brute-force algorithm to match exactly the same lines. (This naive approach has a time complexity of O(N²), but since the typical code length is not very long, I believe it works fine in practice.)
• If a line in before_code does not match, it will be removed with a FadeOut animation. If a line in after_code does not match, it will be added with a FadeIn animation. This transition is visually presented through animation.

This is my first PR! Any advice or suggestions will be appreciated :)

Below are videos demonstrating the difference before and after applying the CodeTransform.

Using Transform (Before)

CodeAnimation.mp4

Using CodeTransform (After)

CodeAnimation.mp4

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested