chore: update sheetLargestUndimmedDetentIndex doc for keyboard handling

Author: t0maboro

versioned_docs/version-7.x/native-stack-navigator.md

@@ -560,6 +560,12 @@ Additionaly there are following options available:
 - `none` - there will be dimming view for all detents levels,
 - `last` - there won't be a dimming view for any detent level.
 
+:::warning
+
+When showing the keyboard for small detent, the system will temporarily resize the sheet above the defined detent, always showing dimming background, even if the user hasn't expanded it manually over the `sheetLargestUndimmedDetentIndex` value.
+
+:::
+
 Defaults to `none`, indicating that the dimming view should be always present.
 
 Only supported on Android and iOS.