chore: Ability to Disable Gravatars (#5027)

fixes: #3853

- Introduced DISABLE_GRAVATAR Global Config, which will stop chatwoot from making API requests to gravatar
- Cleaned up avatar-related logic and centralized it into the avatarable concern
- Added specs for the missing cases
- Added migration for existing installations to move the avatar to attachment, rather than making the API that results in 404.

spec/jobs/avatar/avatar_from_gravatar_job_spec.rb

@@ -0,0 +1,29 @@
+require 'rails_helper'
+
+RSpec.describe Avatar::AvatarFromGravatarJob, type: :job do
+  let(:avatarable) { create(:contact) }
+  let(:email) { 'test@test.com' }
+  let(:gravatar_url) { "https://www.gravatar.com/avatar/#{Digest::MD5.hexdigest(email)}?d=404" }
+
+  it 'enqueues the job' do
+    expect { described_class.perform_later(avatarable, email) }.to have_enqueued_job(described_class)
+      .on_queue('low')
+  end
+
+  it 'will call AvatarFromUrlJob with gravatar url' do
+    expect(Avatar::AvatarFromUrlJob).to receive(:perform_later).with(avatarable, gravatar_url)
+    described_class.perform_now(avatarable, email)
+  end
+
+  it 'will not call AvatarFromUrlJob if DISABLE_GRAVATAR is configured' do
+    with_modified_env DISABLE_GRAVATAR: 'true' do
+      expect(Avatar::AvatarFromUrlJob).not_to receive(:perform_later).with(avatarable, gravatar_url)
+      described_class.perform_now(avatarable, '')
+    end
+  end
+
+  it 'will not call AvatarFromUrlJob if email is blank' do
+    expect(Avatar::AvatarFromUrlJob).not_to receive(:perform_later).with(avatarable, gravatar_url)
+    described_class.perform_now(avatarable, '')
+  end
+end

spec/jobs/avatar/avatar_from_url_job_spec.rb

@@ -0,0 +1,20 @@
+require 'rails_helper'
+
+RSpec.describe Avatar::AvatarFromUrlJob, type: :job do
+  let(:avatarable) { create(:contact) }
+  let(:avatar_url) { 'https://example.com/avatar.png' }
+
+  it 'enqueues the job' do
+    expect { described_class.perform_later(avatarable, avatar_url) }.to have_enqueued_job(described_class)
+      .on_queue('default')
+  end
+
+  it 'will attach avatar from url' do
+    expect(avatarable.avatar).not_to be_attached
+    expect(Down).to receive(:download).with(avatar_url,
+                                            max_size: 15 * 1024 * 1024).and_return(fixture_file_upload(Rails.root.join('spec/assets/avatar.png'),
+                                                                                                       'image/png'))
+    described_class.perform_now(avatarable, avatar_url)
+    expect(avatarable.avatar).to be_attached
+  end
+end