Use HTML swap to display success and error messages

src/email_client.rs

@@ -137,7 +137,7 @@ mod tests {
         Mock::given(header_exists("Authorization"))
             .and(header("Content-Type", "application/json"))
             .and(header("X-Requested-With", "XMLHttpRequest"))
-            .and(path("v1/email"))
+            .and(path("email"))
             .and(method("POST"))
             .and(SendEmailBodyMatcher)
             .respond_with(ResponseTemplate::new(200))