When you have 2 screens in a stack with the bottom one with gestureEnabled=false using the back gesture causes the screen to become unresponsive. This seems to be caused by setting interactivePopGestureRecognizer.enabled = NO as soon as the gesture starts. This causes the gesture to cancel immediately and leaves the screen in an unresponsive state.
<Stack><Screen gestureEnabled={false} /><Screen /></Stack>
To fix this instead of using interactivePopGestureRecognizer.enabled we can leverage the existing delegate that we have in RNScreenStack. In gestureRecognizerShouldBegin we can check if the top screen has gestures enabled.
To make this simpler I moved the gestureEnabled config to Screen instead of HeaderConfig. I think it also makes more sense conceptually since the gesture is tied to the screen and not the header. It also simplifies the android code a bit.
This is a breaking change.
Update
This now only moves the config to screen since a separate fix was merged for the bug.
For customizing back button image we use platform native functionality that is: `setBackIndicatorImage` on iOS and `setHomeAsUpIndicator` on Android.
The reason we don't do that just by setting left item is that we get a couple of things for free such as handling RTL properly, working accessibility features, handling prop for hiding back button and a couple more.
Unfortunately there are some downsides to that approach too. We need to install the back button as an Image component from the JS side, and the extract the image payload on the native side to set it with the navigator. This is specifically problematic in DEV mode where images are loaded asynchronously over HTTP from the packager. In order for that to work we had to employ a few hacks (more comments on that in the code).
When some of config props change or new header items are added we need to perform a header update. This diff adds logic to trigger updating header props when that happens.
This change fixes the problem when header would update to the previous screen configuration as a result of starting swipe back gesture but never restore to the original one in case swipe back gets cancelled (e.g. user didn't swipe far enough). The problem was that as a result of swipe back we'd apply header config changes but after cancel there was no trigger to reset header to the previous state.
