Clean up code: Replace exceptions, remove unused parameters, and fix type annotations in `Animation`, `ShowPartial`, `Create`, and `DrawBorderThenFill`

[irvanalhaq9]

Overview: What does this pull request change?

This pull request introduces some improvements:

1. Replace NotImplementedError to TypeError for invalid input type in ShowPartial , Remove unused parameters and atrributes in DrawBorderThenFill, and Update return type annotation of _get_bounds() in ShowPartial and Create.
2. Fix typo of debug message in Animation.__new__.
3. Removes **kwargs from Animation.__init__, so it raises TypeError immediately when unknown arguments are passed.
4. Adds _original__init__ = __init__ to Animation to prevent AttributeError when using .set_default() with no arguments.

Motivation and Explanation: Why and how do your changes improve the library?

Explanation Point 1:

• Replace NotImplementedError with TypeError in ShowPartial. The docstring explicitly states it raises TypeError when the input is not VMobject.

• In DrawBorderThenFill, parameters and attributes draw_border_animation_config and fill_animation_config are not used at all—they are just stored but never actually do anything. I double-checked with git grep and couldn't find any usage elsewhere. They're also unused in manimgl. So in this PR, I suggest removing them to keep things cleaner and less confusing.

  • Verified with:

    git grep output

    $ git grep draw_border_animation_config
    manim/animation/creation.py:        draw_border_animation_config: dict = {},  # what does this dict accept?
    manim/animation/creation.py:        self.draw_border_animation_config = draw_border_animation_config
    
    $ git grep fill_animation_config
    manim/animation/creation.py:        fill_animation_config: dict = {},
    manim/animation/creation.py:        self.fill_animation_config = fill_animation_config
    

• Update _get_bounds return type annotation to tuple[float, float] in ShowPartial and Create. The return value is used in pointwise_become_partial, which expects two floats.

Explanation Point 2: Only fix typo

Explanation Point 3:

• Remove **kwargs and add use_override to Animation.__init__. So, it raises an exception (TypeError) immediately when unknown arguments are passed. Parameter use_override is added to the __init__, so it will not be considered as unexpected argument when passed from subclass's constructor. Reasons: Currently, Animation silently accepts unexpected keyword arguments without raising an error. This behavior may lead to confusion or silent bugs, since the user might think the argument is doing something, when in fact it is not used at all. For example, running Create(Square(), rate_functions=linear) will pass silently, even though rate_functions is not a valid argument. In contrast, Mobject raises TypeError immediately when unknown arguments are passed, like Square(say="Hello"). # TypeError: Mobject.__init__() got an unexpected keyword argument 'say' NOTE:
  Auto-completion for some default parameters from parent class in some animation classes, such as Create, cannot work properly. For example, if we want to use the rate_func parameter and start typing rate, the auto-completion will suggest rate_functions, which is not a parameter (but a globally imported module). Users might mistakenly think that it's a valid parameter name, but the code won’t work as intended — and the problem is: Manim does not throw an error for that.
• Remove unused final_alpha_value in TransformMatchingAbstractBase as it is never read or used anywhere in the codebase (verified via git grep), and there is no documentation or comment about it. Removing it simplifies the code without affecting functionality.
• angle=TAU is also removed because in Rotating the parameter is radians, not angle, and the default value is already TAU, so no problem removing it. Removing them is consistent with this PR because they are considered unexpected keyword argument, and TypeError is raised.

Explanation Point 4: Adds _original__init__ to Animation. The set_default() method uses cls._original__init__ to restore the original __init__ method when no keyword arguments are passed. However, _original__init__ is not defined in the Animation base class, which causes an error when set_default() is called directly on Animation.

Links to added or changed documentation pages

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