[ios] Disabling PasswordsSettingsTestCase/testEditUsernameFails for iPad devices

This test was already disabled for iOS 12 devices.
But looking through the notes, it looks like it only affects iPads.
Furthermore, I found it affects iOS 13 iPad devices as well.

ios_chrome_settings_eg2tests_module_iPad 7th Gen 13.5.1
https://ci.chromium.org/ui/p/chrome/builders/ci/eg2-device-runner/2400/overview

Nov 3, 2020
ios_chrome_settings_eg2tests_module_iPad 7th Gen 13.5.1
https://ci.chromium.org/ui/p/chrome/builders/ci/eg2-device-runner/2174/overview

TBR=jlebel@chromium.org

Bug: 1140400
Change-Id: I0ec87a993e01258051c0d9facbb6bbabd62f591e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2587407
Commit-Queue: edchin <edchin@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836364}

ios/chrome/browser/ui/settings/password/passwords_settings_egtest.mm

@@ -1521,12 +1521,10 @@ void CopyPasswordDetailWithID(int detail_id) {
 // Checks that attempts to edit a username to a value which is already used for
 // the same domain fails.
 - (void)testEditUsernameFails {
-#if !TARGET_OS_SIMULATOR
-  // TODO(crbug.com/1140400): These seem to fail on device only downstream,
-  // iOS 12.4 only.
-  if (@available(iOS 13, *)) {
-  } else {
-    EARL_GREY_TEST_DISABLED(@"Test disabled on iOS12 device.");
+#if !TARGET_IPHONE_SIMULATOR
+  // TODO(crbug.com/1140400): Fix test for iPad devices.
+  if ([ChromeEarlGrey isIPadIdiom]) {
+    EARL_GREY_TEST_SKIPPED(@"Test disabled on iPad devices.");
   }
 #endif