[ios] Fixes IOSPasswordInfobarController condition.

Context: https://chromium-review.googlesource.com/c/chromium/src/+/1531689
/4/ios/chrome/browser/passwords/ios_password_infobar_controller.mm

TBR=vasilii@chromium.org

Bug: 945478
Change-Id: I2074567bb4d453648c19179462a62c4b31678cca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1572564Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652244}

ios/chrome/browser/passwords/ios_password_infobar_controller.mm

@@ -20,7 +20,7 @@
   auto* delegate = static_cast<IOSChromePasswordManagerInfoBarDelegate*>(
       self.infoBarDelegate);
   NSString* message = delegate->GetDetailsMessageText();
-  if (message.length)
+  if (!message.length)
     return;
 
   [view addFooterLabel:message];