arc: Improve copy on error cases in opt-in flow

chrome/app/chromeos_strings.grdp

Index: chrome/app/chromeos_strings.grdp
diff --git a/chrome/app/chromeos_strings.grdp b/chrome/app/chromeos_strings.grdp
index 76f5e7f8264d3535bbdcdf19cd6f67d4fc6e643e..9720ed436755e09784a609548fbbfa85c968d47c 100644
--- a/chrome/app/chromeos_strings.grdp
+++ b/chrome/app/chromeos_strings.grdp
@@ -6669,7 +6669,7 @@ All users must sign out to continue.
     Cancel
   </message>
   <message name="IDS_ARC_OPT_IN_DIALOG_BUTTON_RETRY" desc="Retry button of the opt-in dialog for Android apps.">
-    Retry
+    Try again
   </message>
   <message name="IDS_ARC_OPT_IN_DIALOG_BUTTON_SEND_FEEDBACK" desc="Send feedback button of the opt-in dialog for Android apps.">
     Send feedback
@@ -6721,7 +6721,7 @@ All users must sign out to continue.
     Network error
   </message>
   <message name="IDS_ARC_SIGN_IN_SERVICE_UNAVAILABLE_ERROR" desc="Android sign-in error because of service is unavailable">
-    Service unavailable
+    Couldn't reach Google Play. Try again now.
   </message>
   <message name="IDS_ARC_SIGN_IN_BAD_AUTHENTICATION_ERROR" desc="Android sign-in error because of bad authentification">
     Bad authentication