Startify window does not update to reflect new g:startify_padding_left value

I am trying to hack in support for a centered Startify window, and while I can achieve centering, once Vim starts I am stuck with the value initially set to `g:startify_padding_left` regardless of when I set the padding variable. So when I open a vsplit with a Startify window, despite `g:startify_padding_left` being set to the padding I desire, Startify itself will keep the padding value used when Vim was opened

Open fresh neovim, centered how i want. `g:startify_padding_left` = 66

Open a new Startify window during the same session, the padding doesn't update. `g:startify_padding_left` = 13

I would really like to be able to do this. I could write a PR if needed, I have Vimscript experience

Locate where the Startify window is created and where g:startify_padding_left is read. Reproduce the issue by changing the value after opening Vim, then opening a new Startify window; done means the new window uses the current padding value rather than the value from startup.

Written by the indexing model from the issue text.