feat: Update swagger to openapi 3.0.4, update request payloads with examples (#11533)

# Pull Request Template

## Description

Updates the public swagger spec to be OpenAPI 3.0.4 compliant. Regarding
#7893, I'm investigating the use of
[oas_rails](https://github.com/a-chacon/oas_rails) to auto-generate the
documentation along with correct expected payloads.
Mostly fixes #10531, related to #7893

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality not to work as expected)
- [ ] This change requires a documentation update

## How Has This Been Tested?

Copied spec into swagger editor, reviewed outputs:

![openapi](https://github.com/user-attachments/assets/bd43f895-74bb-4373-ba6d-c5b190b699dd)

Note that this shows two errors with the `DELETE` endpoints as
technically these should not have a `requestBody` - in which case we
should be making use of another HTTP verb or another endpoint.

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Daniel Jimenez <devildan.knex@gmail.com>
Co-authored-by: Daniel Jimenez <daniel.jimenez@spark64.com>

swagger/definitions/resource/conversation.yml

@@ -10,27 +10,82 @@ properties:
   account_id:
     type: number
     description: Account Id
+  uuid:
+    type: string
+    description: UUID of the conversation
+  additional_attributes:
+    type: object
+    description: The object containing additional attributes related to the conversation
+  agent_last_seen_at:
+    type: number
+    description: The last activity at of the agent
+  assignee_last_seen_at:
+    type: number
+    description: The last activity at of the assignee
+  can_reply:
+    type: boolean
+    description: Whether the conversation can be replied to
+  contact_last_seen_at:
+    type: number
+    description: The last activity at of the contact
+  custom_attributes:
+    type: object
+    description: The object to save custom attributes for conversation, accepts custom attributes key and value
   inbox_id:
     type: number
     description: ID of the inbox
+  labels:
+    type: array
+    items:
+      type: string
+    description: The labels of the conversation
+  muted:
+    type: boolean
+    description: Whether the conversation is muted
+  snoozed_until:
+    type: number
+    description: The time at which the conversation will be unmuted
   status:
     type: string
     enum: ['open', 'resolved', 'pending']
     description: The status of the conversation
+  created_at:
+    type: number
+    description: The time at which conversation was created
+  updated_at:
+    type: number
+    description: The time at which conversation was updated
   timestamp:
     type: string
     description: The time at which conversation was created
-  contact_last_seen_at:
-    type: string
-  agent_last_seen_at:
-    type: string
+  first_reply_created_at:
+    type: number
+    description: The time at which the first reply was created
   unread_count:
     type: number
     description: The number of unread messages
-  additional_attributes:
+  last_non_activity_message:
     type: object
-    description: The object containing additional attributes related to the conversation
-  custom_attributes:
+    $ref: '#/components/schemas/message'
+    description: The last non activity message
+  last_activity_at:
+    type: number
+    description: The last activity at of the conversation
+  priority:
+    type: string
+    description: The priority of the conversation
+  waiting_since:
+    type: number
+    description: The time at which the conversation was waiting
+  sla_policy_id:
+    type: number
+    description: The ID of the SLA policy
+  applied_sla:
     type: object
-    description: The object to save custom attributes for conversation, accepts custom attributes key and value
-    example: { attribute_key: attribute_value, priority_conversation_number: 3 }
+    description: The applied SLA
+  sla_events:
+    type: array
+    items:
+      type: object
+      description: SLA event objects
+