Update third party auth login page message.

LEARNER-5258

common/djangoapps/third_party_auth/tests/specs/base.py

@@ -123,7 +123,7 @@ class HelperMixin(object):
         """Asserts failure on /login for missing social auth looks right."""
         self.assertEqual(403, response.status_code)
         self.assertIn(
-            u"successfully logged into your %s account, but this account isn't linked" % self.provider.name,
+            u"successfully signed in to your %s account, but this account isn't linked" % self.provider.name,
             response.content.decode(response.charset)
         )
 

openedx/core/djangoapps/user_authn/views/login.py

@@ -57,9 +57,9 @@ def _do_third_party_auth(request):
                 username=username, backend_name=backend_name)
         )
         message = Text(_(
-            u"You've successfully logged into your {provider_name} account, "
+            u"You've successfully signed in to your {provider_name} account, "
             u"but this account isn't linked with your {platform_name} account yet. {blank_lines}"
-            u"Use your {platform_name} username and password to log into {platform_name} below, "
+            u"Use your {platform_name} username and password to sign in to {platform_name} below, "
             u"and then link your {platform_name} account with {provider_name} from your dashboard. {blank_lines}"
             u"If you don't have an account on {platform_name} yet, "
             u"click {register_label_strong} at the top of the page."