Login and Registration: Fix failing test for "email already exists" r…

…egistration error improvement.

Follow-up to [52074].

Fixes #53631.

git-svn-id: https://develop.svn.wordpress.org/trunk@52075 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/rest-api/rest-users-controller.php

@@ -1445,7 +1445,10 @@ public function test_create_existing_network_user_on_sub_site_has_error() {
 			if ( 'user_name' === $error['code'] ) {
 				$this->assertSame( 'Sorry, that username already exists!', $error['message'] );
 			} else {
-				$this->assertSame( 'Sorry, that email address is already used!', $error['message'] );
+				$expected = '<strong>Error:</strong> This email address is already registered. ' .
+							'<a href="http://rest.wordpress.org/wp-login.php">Log in</a> with ' .
+							'this address or choose another one.';
+				$this->assertSame( $expected, $error['message'] );
 			}
 		}
 	}