chore: Refactor Response Bot Data Schema (#8011)

This PR refactors the schema we introduced in #7518 based on the feedback from production tests. Here is the change log

- Decouple Inbox association to a new table inbox_response_sources -> this lets us share the same response source between multiple inboxes
- Add a status field to responses. This ensures that, by default, responses are created in pending status. You can do quality assurance before making them active. In future, this status can be leveraged by the bot to auto-generate response questions from conversations which require a handoff
- Add response_source association to responses and remove hard dependency from response_documents. This lets users write free-form question answers based on conversations, which doesn't necessarily need a response source.

spec/enterprise/controllers/api/v1/accounts/response_sources_controller_spec.rb

@@ -3,7 +3,6 @@ require 'rails_helper'
 RSpec.describe 'Response Sources API', type: :request do
   let!(:account) { create(:account) }
   let!(:admin) { create(:user, account: account, role: :administrator) }
-  let!(:inbox) { create(:inbox, account: account) }
 
   before do
     skip('Skipping since vector is not enabled in this environment') unless Features::ResponseBotService.new.vector_extension_enabled?
@@ -44,7 +43,6 @@ RSpec.describe 'Response Sources API', type: :request do
         response_source: {
           name: 'Test',
           source_link: 'http://test.test',
-          inbox_id: inbox.id,
           response_documents_attributes: [
             { document_link: 'http://test1.test' },
             { document_link: 'http://test2.test' }
@@ -75,7 +73,7 @@ RSpec.describe 'Response Sources API', type: :request do
   end
 
   describe 'POST /api/v1/accounts/{account.id}/response_sources/{response_source.id}/add_document' do
-    let!(:response_source) { create(:response_source, account: account, inbox: inbox) }
+    let!(:response_source) { create(:response_source, account: account) }
     let(:valid_params) do
       { document_link: 'http://test.test' }
     end
@@ -103,7 +101,7 @@ RSpec.describe 'Response Sources API', type: :request do
   end
 
   describe 'POST /api/v1/accounts/{account.id}/response_sources/{response_source.id}/remove_document' do
-    let!(:response_source) { create(:response_source, account: account, inbox: inbox) }
+    let!(:response_source) { create(:response_source, account: account) }
     let!(:response_document) { response_source.response_documents.create!(document_link: 'http://test.test') }
     let(:valid_params) do
       { document_id: response_document.id }

spec/enterprise/controllers/enterprise/api/v1/accounts/inboxes_controller_spec.rb

@@ -71,7 +71,9 @@ RSpec.describe 'Enterprise Inboxes API', type: :request do
       end
 
       it 'returns all response_sources belonging to the inbox to administrators' do
-        response_source = create(:response_source, account: account, inbox: inbox)
+        response_source = create(:response_source, account: account)
+        inbox.response_sources << response_source
+        inbox.save!
         get "/api/v1/accounts/#{account.id}/inboxes/#{inbox.id}/response_sources",
             headers: administrator.create_new_auth_token,
             as: :json