[ios] Creates Strings for Settings swipe down action sheet.

Creates Strings needed for Rubberband action sheet per:
https://bugs.chromium.org/p/chromium/issues/detail?id=980037#c10

Bug: 1006304
Change-Id: I421372e09285804acce07540099f79d15646d491
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816746Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699827}

ios/chrome/app/strings/ios_strings.grd

@@ -1473,6 +1473,15 @@ Handoff must also be enabled in the General section of Settings, and your device
       </message>
       <message name="IDS_IOS_SETTINGS_TOOLBAR_DELETE" desc="Label of the button displayed on the bottom toolbar of the settings' collections when they are in edit mode. Pressing this button deletes the currently selected items.">
         Delete
+      </message>
+        <message name="IDS_IOS_SETTINGS_SWIPE_DOWN_MESSAGE" desc="Message displayed whenever a user tries to dismiss a Settings screen which is being edited, or information is being added to it.">
+        Are you sure you want to discard your changes?
+      </message>
+      <message name="IDS_IOS_SETTINGS_SWIPE_DOWN_DISCARD" desc="Button displayed along with a message alert whenever a user tries to dismiss a Settings screen which is being edited, or information is being added to it. Selecting this option will discard the current changes and dismiss the screen.">
+        Discard Changes
+      </message>
+      <message name="IDS_IOS_SETTINGS_SWIPE_DOWN_KEEP" desc="Button displayed along with a message alert whenever a user tries to dismiss a Settings screen which is being edited, or information is being added to it. Selecting this option will dismiss the message alert, and will keep displaying the settings screen.">
+        Keep Editing
       </message>
       <message name="IDS_IOS_TOGGLE_SETTING_SWITCH_ACCESSIBILITY_HINT" desc="Action hint for any switch in settings. This is spoken by VoiceOver. [iOS only]">
         Double tap to toggle setting

ios/chrome/app/strings/ios_strings_grd/IDS_IOS_SETTINGS_SWIPE_DOWN.png.sha1

+86557c53bab25e735c9becf4120f6a1b9cc66cb3
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