[iOS] Update navigation bar visibility logic

* Update navigation bar visibility to account for top toolbars state
* Hide navigation bar when top toolbars are hidden

Author: eslamwael74

ios/Classes/PTFlutterDocumentController.m

@@ -1037,7 +1037,7 @@ - (void)applyViewerSettings
     const BOOL hideTopToolbars = self.topToolbarsHidden;
     self.controlsHidden = hideTopToolbars;
 
-    const BOOL hideTopAppNavBar = self.topAppNavBarHidden;
+    const BOOL hideTopAppNavBar = (self.topAppNavBarHidden || self.topToolbarsHidden);
     const BOOL translucent = hideTopAppNavBar;
     [self.navigationController setNavigationBarHidden:hideTopAppNavBar animated:NO];
     self.navigationController.navigationBar.translucent = translucent;