In sync passphrase dialog reset left bar button and title to saved values

ios/chrome/browser/ui/settings/sync_encryption_passphrase_collection_view_controller.mm

Index: ios/chrome/browser/ui/settings/sync_encryption_passphrase_collection_view_controller.mm
diff --git a/ios/chrome/browser/ui/settings/sync_encryption_passphrase_collection_view_controller.mm b/ios/chrome/browser/ui/settings/sync_encryption_passphrase_collection_view_controller.mm
index 5c1f13d5e4b6da5f73ba0c7edb8a3688d0397c16..f0d01bc334032275bb2f090ac52e1ddc7030d5e0 100644
--- a/ios/chrome/browser/ui/settings/sync_encryption_passphrase_collection_view_controller.mm
+++ b/ios/chrome/browser/ui/settings/sync_encryption_passphrase_collection_view_controller.mm
@@ -430,8 +430,10 @@ const CGFloat kSpinnerButtonPadding = 18;
     return;
   isDecryptionProgressShown_ = NO;
 
-  self.navigationItem.leftBarButtonItem = savedLeftButton_ = nil;
-  self.title = savedTitle_ = nil;
+  self.navigationItem.leftBarButtonItem = savedLeftButton_;
+  savedLeftButton_ = nil;
+  self.title = savedTitle_;
+  savedTitle_ = nil;
   [self setRightNavBarItem];
 }