OpenGLVMobject fix data alignment to support interpolating families

[MrDiver]

Overview: What does this pull request change?

This pull request extends

• Fixed :meth:.OpenGLVMobject.pointwise_become_partial to improve stroke rendering #2714

with fixing data alignment which then fixes some interpolation issues with families. The main problem is that the code in OpenGLMobject align_data on the first look serves the same purpose as the code in Mobject but the problem is that the null_point_alignment is missing.

This PR adds back the nullpoint alignment but with integrating it in to the current structure of OpenGLMobject because it is more modern and should probably be ported over to Mobject at some point.

Adding null_point_align to OpenGLMobject
Adding null_point_align_family to OpenGLMobject

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

Further improving the render capabilities of the OpenGL Renderer and the shrinking the difference in the output of the gl and cairo renderer

class Bench(Scene):
    def construct(self):
        circle = DashedVMobject(Circle())
        circle2 = Circle()
        offset = ValueTracker(0)
        circle.add_updater(lambda m: m.become(DashedVMobject(Circle(),dash_offset=offset.get_value())))
        self.add(circle)
        self.play(offset.animate.increment_value(3))
        circle.suspend_updating()
        self.play(Transform(circle,circle2),run_time=5)

Bench.mp4

Cairo result to be aspired

Bench.mp4

Further Information and Comments

There still seems to be a problem with the other data alignments because the opacity on a transition is still somehow missing from somewhere.

Bench.mp4

Maybe this can be fixed in a future PR

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

[MrDiver]

THIS HAS BEEN HERE FOR SOOOO LONG, I think no one needs it anyway 🤣