chore: Handle conversation participation creation race condition error (#9449)

We observed some race condition errors in the conversation participation listener while trying to create a conversation participation assignment. This PR handles this error and also adds additional debug information for future.

fixes: https://linear.app/chatwoot/issue/CW-3296/activerecordrecordnotunique-pguniqueviolation-error-duplicate-key

## Changelog

- handles `ActiveRecord::RecordNotUnique, ActiveRecord::RecordInvald` errors so that they won't pollute sentry
- Adds a debug statement to log the cases
- Add previous_changes into the dispatcher so that we know the exact attribute changes which trigger `assignee_changed, team_changed` events ( would be handy in future )

spec/models/conversation_spec.rb

@@ -156,7 +156,7 @@ RSpec.describe Conversation do
                                                                  changed_attributes: nil, performed_by: nil)
       expect(Rails.configuration.dispatcher).to have_received(:dispatch)
         .with(described_class::ASSIGNEE_CHANGED, kind_of(Time), conversation: conversation, notifiable_assignee_change: true,
-                                                                changed_attributes: nil, performed_by: nil)
+                                                                changed_attributes: changed_attributes, performed_by: nil)
       expect(Rails.configuration.dispatcher).to have_received(:dispatch)
         .with(described_class::CONVERSATION_UPDATED, kind_of(Time), conversation: conversation, notifiable_assignee_change: true,
                                                                     changed_attributes: changed_attributes, performed_by: nil)