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/mailboxes/reply_mailbox_spec.rb

@@ -19,7 +19,7 @@ RSpec.describe ReplyMailbox, type: :mailbox do
       before do
         # this UUID is hardcoded in the reply.eml, that's why we are updating this
         conversation.uuid = '6bdc3f4d-0bec-4515-a284-5d916fdde489'
-        conversation.save
+        conversation.save!
 
         described_subject
       end
@@ -129,7 +129,7 @@ RSpec.describe ReplyMailbox, type: :mailbox do
       before do
         # this UUID is hardcoded in the reply.eml, that's why we are updating this
         conversation.uuid = '6bdc3f4d-0bec-4515-a284-5d916fdde489'
-        conversation.save
+        conversation.save!
       end
 
       it 'add the mail content as new message on the conversation' do

spec/mailboxes/support_mailbox_spec.rb

@@ -32,7 +32,7 @@ RSpec.describe SupportMailbox, type: :mailbox do
     before do
       # this email is hardcoded in the support.eml, that's why we are updating this
       channel_email.email = 'care@example.com'
-      channel_email.save
+      channel_email.save!
     end
 
     describe 'covers email address format' do
@@ -121,7 +121,7 @@ RSpec.describe SupportMailbox, type: :mailbox do
       before do
         # this email is hardcoded eml fixture file that's why we are updating this
         channel_email.email = 'support@chatwoot.com'
-        channel_email.save
+        channel_email.save!
       end
 
       it 'create new contact with original sender' do