fix: Revoke Linear OAuth token when integration is deleted (#11838)

When users delete the Linear integration from their Chatwoot dashboard,
the access token remains valid in Linear's system. This causes the
integration to still appear as connected in Linear's UI, even though
it's been removed from Chatwoot. Users need to manually disconnect from
Linear's side to fully remove the integration.


https://www.loom.com/share/5c102cbdf02e49bcb7a6fa6d409b531a?sid=0c664250-c867-4fc8-b44d-e1c1165337a7

spec/controllers/api/v1/accounts/integrations/linear_controller_spec.rb

@@ -14,6 +14,12 @@ RSpec.describe 'Linear Integration API', type: :request do
 
   describe 'DELETE /api/v1/accounts/:account_id/integrations/linear' do
     it 'deletes the linear integration' do
+      # Stub the HTTP call to Linear's revoke endpoint
+      allow(HTTParty).to receive(:post).with(
+        'https://api.linear.app/oauth/revoke',
+        anything
+      ).and_return(instance_double(HTTParty::Response, success?: true))
+
       delete "/api/v1/accounts/#{account.id}/integrations/linear",
              headers: agent.create_new_auth_token,
              as: :json