chore: Use "create!" and "save!" bang methods when not checking the result (#5358)

* Use "create!" when not checking for errors on the result
* Use "save!" when not checking the result

spec/models/campaign_spec.rb

@@ -15,7 +15,7 @@ RSpec.describe Campaign, type: :model do
     let(:campaign) { build(:campaign, inbox: website_inbox, display_id: nil, trigger_rules: { url: 'https://test.com' }) }
 
     before do
-      campaign.save
+      campaign.save!
       campaign.reload
     end
 

spec/models/conversation_spec.rb

@@ -19,7 +19,7 @@ RSpec.describe Conversation, type: :model do
     let(:conversation) { build(:conversation, display_id: nil) }
 
     before do
-      conversation.save
+      conversation.save!
       conversation.reload
     end