Burning animation of vicious ivy and walking leaf have vertical offset

[Brockengespenst]

SuperTux version: latest development (ef111b4e5b398ea4875ada1762b24448419167a9)

Expected behavior

Burning animation of vicious ivy and walking leaf smoothly fade over from non-burning animation without vertical offset.

Actual behavior

Burning animation has an offset in vertical direction so that it moves down "into the ground". See video for details.

https://github.com/SuperTux/supertux/assets/155102424/69487efa-5128-42f8-a628-b871a81eaf1c

Steps to reproduce actual behavior

Start first forest level, gain fireflower and shoot at vicious ivy and walking leaf.

[Rusty-Box]

They're not the only enemy that has this issue but we are aware of it. We kept it for now as we will revamp the way we handle burning animations in a similar fashion we handle enemies freezing soon.

[ghost]

I think it is minor because it is only a very small graphics artifact