Draft: fix(iOS): Reorder back button setup logic so iOS renders it correctly when displayMode=minimal

[kmichalikk]

Description

Partially fixes #2991. Unfortunately, not all cases are covered; see below.

When navigating from screen with headerShown: false to a screen that has a back button with displayMode=minimal, the width of the button appears to be the same as if it was meant for the first screen, with space allocated for a label that is not visible.

Changes

Simply moving the line that updates the displayMode after the rest of back button's setup code, solves the problem for apps which use displayMode=minimal.

Before

header-misaligned-before.mov

After

header-misaligned-after.mov

What still needs fixing

When mixing headerShown=false, displayMode=default and displayMode=minimal, the screen with displayMode=minimal still doesn't work. For now, please use workarounds suggested by the community in #2991.

header-misaligned-default.mov

Testing

Use Test2991, change headerShown, and headerBackButtonDisplayMode. For changes to take effect, it's good to close and reopen the app on the phone.

[kkafar]

This looks promising, but we need to verify that the second interaction described in the PR (the one that still requires fixing) is not a regression introduced by this PR & is reproducible on main branch.

Could you confirm that?

[kmichalikk]

It looked fine-ish until I tried the other way around, from first to third, to first, to second. Now second is always minimal. I'd say it's not an improvement then. Converting it to Draft.