fix: hide background for unfocused header in fade

Otherwise the header background below shows up when header mode is none

Author: satya164

src/TransitionConfigs/HeaderStyleInterpolators.tsx

@@ -98,10 +98,7 @@ export function forFade({
     leftButtonStyle: { opacity },
     rightButtonStyle: { opacity },
     titleStyle: { opacity },
-    // For both bakgrounds to cross-fade properly, we don't want to animate the one below from 0
-    // Because 2 semitransparent backgrounds on top of each other will always have some transparency
-    // And this will make the stuff under them visible (usually white) which isn't expected
-    backgroundStyle: { opacity: current },
+    backgroundStyle: { opacity },
   };
 }