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/mailers/conversation_reply_mailer_spec.rb

@@ -54,15 +54,15 @@ RSpec.describe ConversationReplyMailer, type: :mailer do
 
       it 'renders the subject in conversation as reply' do
         conversation.additional_attributes = { 'mail_subject': 'Mail Subject' }
-        conversation.save
-        new_message.save
+        conversation.save!
+        new_message.save!
         expect(mail.subject).to eq('Re: Mail Subject')
       end
 
       it 'not have private notes' do
         # make the message private
         private_message.private = true
-        private_message.save
+        private_message.save!
 
         expect(mail.body.decoded).not_to include(private_message.content)
         expect(mail.body.decoded).to include(message.content)
@@ -104,7 +104,7 @@ RSpec.describe ConversationReplyMailer, type: :mailer do
       let(:mail) { described_class.reply_without_summary(message_2.conversation, message_2.id).deliver_now }
 
       before do
-        message_2.save
+        message_2.save!
       end
 
       it 'renders the default subject' do
@@ -113,14 +113,14 @@ RSpec.describe ConversationReplyMailer, type: :mailer do
 
       it 'renders the subject in conversation' do
         conversation.additional_attributes = { 'mail_subject': 'Mail Subject' }
-        conversation.save
+        conversation.save!
         expect(mail.subject).to eq('Mail Subject')
       end
 
       it 'not have private notes' do
         # make the message private
         private_message.private = true
-        private_message.save
+        private_message.save!
         expect(mail.body.decoded).not_to include(private_message.content)
       end