fix: Update account data seeder to avoid invalid information (#7673)

- The message sender was incorrect. Incoming messages were created under the contact's name, and outgoing messages were created under the user's name instead of the reverse.
- The seed user's email address was incorrect in the message data.
- The Sendmail configuration overrode the Letter Opener config which made it difficult to test the email.
- This PR also fixes an ESLint lint issue on develop.

lib/seeders/account_seeder.rb

@@ -96,16 +96,19 @@ class Seeders::AccountSeeder
   def create_messages(conversation:, messages:)
     messages.each do |message_data|
       sender = find_message_sender(conversation, message_data)
-      conversation.messages.create!(message_data.slice('content', 'message_type').merge(account: conversation.inbox.account, sender: sender,
-                                                                                        inbox: conversation.inbox))
+      conversation.messages.create!(
+        message_data.slice('content', 'message_type').merge(
+          account: conversation.inbox.account, sender: sender, inbox: conversation.inbox
+        )
+      )
     end
   end
 
   def find_message_sender(conversation, message_data)
     if message_data['message_type'] == 'incoming'
-      User.find_by(email: message_data['sender']) if message_data['sender'].present?
-    else
       conversation.contact
+    elsif message_data['sender'].present?
+      User.find_by(email: message_data['sender'])
     end
   end