[Signin iOS] Update title in merging data dialog

ios/chrome/app/strings/ios_chromium_strings.grd

Index: ios/chrome/app/strings/ios_chromium_strings.grd
diff --git a/ios/chrome/app/strings/ios_chromium_strings.grd b/ios/chrome/app/strings/ios_chromium_strings.grd
index 04792e1acc82980bcee6fb51d5263843136da59a..c347380e13a02ad9a3e2f9136eb50b96e1158633 100644
--- a/ios/chrome/app/strings/ios_chromium_strings.grd
+++ b/ios/chrome/app/strings/ios_chromium_strings.grd
@@ -210,6 +210,9 @@ locale.  The strings in this file are specific to iOS.
       <message name="IDS_IOS_OPTIONS_ENABLE_PHYSICAL_WEB_DETAILS" desc="The detailed description of an option to enable scanning for nearby devices broadcasting URLs.">
         Discover web pages sent by nearby objects. When Bluetooth is turned on, Chromium can gather web pages associated with objects around you and send them anonymously to Google to find the most useful ones. <ph name="BEGIN_LINK">BEGIN_LINK</ph>Learn more<ph name="END_LINK">END_LINK</ph>
       </message>
+      <message name="IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SIGNIN" desc="The title of the Import Data settings screen when signing in. [30em]">
+        Sign in to Chromium
+      </message>
       <message name="IDS_IOS_OPTIONS_PRIVACY_FOOTER" desc="Footer for the clear browsing data dialog [Length: 300em] [iOS only]">
         Chromium may use web services to improve your browsing experience. You may optionally disable these services. <ph name="BEGIN_LINK">BEGIN_LINK</ph>Learn more<ph name="END_LINK">END_LINK</ph>
       </message>