fix(header): fix collapsing iOS header when using with split pane

[liamdebeasi]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: #19541

What is the new behavior?

1. Check the correct bounding box in the IO handler
2. Account for any left/right offsets when doing nav transitions

Does this introduce a breaking change?

• Yes
• No

Other information

[brandyscarney]

Released dev build for this 4.11.0-dev.201910021714.944a660 cc @mhartington

[brandyscarney]

I'm still seeing this 🤔

[liamdebeasi]

@brandyscarney Are you testing the dev build above? I'm testing it on your conference app changes and everything looks like it's working fine

[liamdebeasi]

Ok I tagged the wrong issue. Updated with correct issue

[brandyscarney]

Okay perfect, testing the right issue out and this is fixed! 🎉