fix: Skip redundant contact saves in ContactIdentifyAction (#13778)

When the SDK sends identify calls with identical payloads (common on
every page load), `save!` fires even though no attributes changed. While
Rails skips the actual UPDATE SQL, it still opens a transaction, runs
all callbacks (including validation queries like `Contact Exists?`), and
triggers `after_commit` hooks — all for a no-op.

This adds a `changed?` guard before `save!` to skip it entirely when no
attributes have actually changed.

**How to test**

- Trigger an identify call via the SDK with a contact's existing
attributes (same name, email, custom_attributes, etc.)
- The contact should not fire a save (no transaction, no callbacks)
- Trigger an identify call with a changed attribute — save should work
normally

**What changed**

- `ContactIdentifyAction#update_contact`: guard `save!` with `changed?`
check
- Added specs to verify `save!` is skipped for unchanged params and
avatar job still enqueues independently

app/actions/contact_identify_action.rb

@@ -104,7 +104,7 @@ class ContactIdentifyAction
     # blank identifier or email will throw unique index error
     # TODO: replace reject { |_k, v| v.blank? } with compact_blank when rails is upgraded
     @contact.discard_invalid_attrs if discard_invalid_attrs
-    @contact.save!
+    @contact.save! if @contact.changed?
     enqueue_avatar_job
   end
 

spec/actions/contact_identify_action_spec.rb

@@ -145,5 +145,24 @@ describe ContactIdentifyAction do
         expect(contact.phone_number).to be_nil
       end
     end
+
+    context 'when params have not changed' do
+      it 'skips save and does not issue an UPDATE query' do
+        contact.update!(name: 'test', identifier: 'test_id', custom_attributes: { test: 'test', test1: 'test1' })
+        params = { name: 'test', identifier: 'test_id', custom_attributes: { test: 'test', test1: 'test1' } }
+
+        # any_instance is needed because merge lookup can reassign @contact to a different Ruby object
+        expect_any_instance_of(Contact).not_to receive(:save!) # rubocop:disable RSpec/AnyInstance
+        described_class.new(contact: contact, params: params).perform
+      end
+
+      it 'still enqueues avatar job even when attributes have not changed' do
+        contact.update!(name: 'test')
+        params = { name: 'test', avatar_url: 'https://chatwoot-assets.local/sample.png' }
+
+        expect(Avatar::AvatarFromUrlJob).to receive(:perform_later).with(contact, params[:avatar_url]).once
+        described_class.new(contact: contact, params: params).perform
+      end
+    end
   end
 end