fix: Avoid joining tables to fix the distinct value query (#7965)

DISTINCT query with custom attributes return an error. To avoid the error, this PR refactors the query to include tags only when it is required.

Fixes #7931
Fixes #7836

Co-authored-by: Sojan Jose <sojan@pepalo.com>

spec/services/contacts/filter_service_spec.rb

@@ -15,7 +15,7 @@ describe Contacts::FilterService do
     create(:inbox_member, user: first_user, inbox: inbox)
     create(:inbox_member, user: second_user, inbox: inbox)
     create(:conversation, account: account, inbox: inbox, assignee: first_user, contact: en_contact)
-    create(:conversation, account: account, inbox: inbox)
+    create(:conversation, account: account, inbox: inbox, contact: el_contact)
     Current.account = account
 
     create(:custom_attribute_definition,
@@ -38,8 +38,7 @@ describe Contacts::FilterService do
 
   describe '#perform' do
     before do
-      en_contact.add_labels(%w[random_label support])
-      el_contact.update_labels('random_label')
+      en_contact.update_labels(%w[random_label support])
       cs_contact.update_labels('support')
 
       en_contact.update!(custom_attributes: { contact_additional_information: 'test custom data' })
@@ -60,6 +59,70 @@ describe Contacts::FilterService do
         ]
       end
 
+      context 'with label filter' do
+        it 'returns equal_to filter results properly' do
+          params[:payload] = [
+            {
+              attribute_key: 'labels',
+              filter_operator: 'equal_to',
+              values: ['support'],
+              query_operator: nil
+            }.with_indifferent_access
+          ]
+
+          result = filter_service.new(params, first_user).perform
+          expect(result[:contacts].length).to be 2
+          expect(result[:contacts].first.label_list).to include('support')
+          expect(result[:contacts].last.label_list).to include('support')
+        end
+
+        it 'returns not_equal_to filter results properly' do
+          params[:payload] = [
+            {
+              attribute_key: 'labels',
+              filter_operator: 'not_equal_to',
+              values: ['support'],
+              query_operator: nil
+            }.with_indifferent_access
+          ]
+
+          result = filter_service.new(params, first_user).perform
+          expect(result[:contacts].length).to be 1
+          expect(result[:contacts].first.id).to eq el_contact.id
+        end
+
+        it 'returns is_present filter results properly' do
+          params[:payload] = [
+            {
+              attribute_key: 'labels',
+              filter_operator: 'is_present',
+              values: [],
+              query_operator: nil
+            }.with_indifferent_access
+          ]
+
+          result = filter_service.new(params, first_user).perform
+          expect(result[:contacts].length).to be 2
+          expect(result[:contacts].first.label_list).to include('support')
+          expect(result[:contacts].last.label_list).to include('support')
+        end
+
+        it 'returns is_not_present filter results properly' do
+          params[:payload] = [
+            {
+              attribute_key: 'labels',
+              filter_operator: 'is_not_present',
+              values: [],
+              query_operator: nil
+            }.with_indifferent_access
+          ]
+
+          result = filter_service.new(params, first_user).perform
+          expect(result[:contacts].length).to be 1
+          expect(result[:contacts].first.id).to eq el_contact.id
+        end
+      end
+
       it 'filter contacts by additional_attributes' do
         params[:payload] = payload
         result = filter_service.new(params, first_user).perform
@@ -83,25 +146,7 @@ describe Contacts::FilterService do
         expect(result[:contacts].first.name).to eq(en_contact.name)
       end
 
-      it 'filter contact by tags' do
-        label_id = cs_contact.labels.last.id
-        params[:payload] = [
-          {
-            attribute_key: 'labels',
-            filter_operator: 'equal_to',
-            values: [label_id],
-            query_operator: nil
-          }.with_indifferent_access
-        ]
-
-        result = filter_service.new(params, first_user).perform
-        expect(result[:contacts].length).to be 2
-        expect(result[:contacts].first.label_list).to include('support')
-        expect(result[:contacts].last.label_list).to include('support')
-      end
-
       it 'filter by custom_attributes and labels' do
-        label_id = cs_contact.labels.last.id
         params[:payload] = [
           {
             attribute_key: 'customer_type',
@@ -112,7 +157,7 @@ describe Contacts::FilterService do
           {
             attribute_key: 'labels',
             filter_operator: 'equal_to',
-            values: [label_id],
+            values: ['support'],
             query_operator: 'AND'
           }.with_indifferent_access,
           {