Properly stub MailBluster calls in FactoryBot user creation

spec/factories/users.rb

@@ -80,22 +80,24 @@ FactoryBot.define do
     last_sign_in_at { Date.today }
     is_disabled { false }
 
-    url_mailbluster = 'https://api.mailbluster.com/api/leads/'
-    response_body = "{
-      \"message\": \"Lead created\",
-      \"lead\": {
-        \"id\": 329395,
-        \"firstName\": \"#{name}\",
-        \"lastName\": \"\",
-        \"fullName\": \"#{name}\",
-        \"email\": \"#{email}\",
-        \"subscribed\": true,
-        \"tags\": [
-          #{ENV['OSEM_NAME'] || 'snapcon'}
-        ],
-      }
-    }"
-    WebMock.stub_request(:post, url_mailbluster)
+    after(:build) do |user|
+      url_mailbluster = 'https://api.mailbluster.com/api/leads/'
+      response_body = "{
+        \"message\": \"Lead created\",
+        \"lead\": {
+          \"id\": 329395,
+          \"firstName\": \"#{user.name}\",
+          \"lastName\": \"\",
+          \"fullName\": \"#{user.name}\",
+          \"email\": \"#{user.email}\",
+          \"subscribed\": true,
+          \"tags\": [
+            #{ENV['OSEM_NAME'] || 'snapcon'}
+          ],
+        }
+      }"
+      WebMock.stub_request(:post, url_mailbluster)
+    end
     # Called by every user creation
 
     after(:create) do |user|