fix: entering fullscreen mode the first time results in showing the first slide

[nietsmmar]

Description

When pressing the Enter full screen for the first time, my presentation goes back to slide 1. When switching between full screen and normal mode afterwards it works. It is just not working when entering full screen the first time. (Tested in build for Linux and Chrome)

I tried building a minimal reproducible Example. Sadly I have not figured out yet what is causing this error. This happens in my main App but not in a simple example. I will keep trying to build a working example to showcase the problem.

I checked the code in FlutterDeckFullscreenManager and could not see anything that could cause this.

Steps To Reproduce

1. Go to some slide in your deck (not first one)
2. Click on Enter full screen

Expected Behavior

Full screen mode is entered, but slide stays the same.