[UI] Tree select in form fields (#12217)

* Add TreeField component

* Add chevrons in dropdown menu

* Custom node rendering

* Add childIdentifier

* Ensure full value gets displayed

* Fix for search results

* Refactor old renderers

* Override field types

* use definition filters

* Better location validation messages

* Tweaks

* Fix unit test

* Include icon

* Fix playwright test

* Fix call to onValueChange

* Updated playwright tests

* Use pathstring in selectedLabel (if available)

* Mark structural nodes

* Retain selected value when dropdown open

* Add better placeholder values

* Simplify field selection

src/frontend/tests/pages/pui_stock.spec.ts

@@ -499,7 +499,8 @@ test('Stock - Tracking', async ({ browser }) => {
 
   // Navigate to the "stock tracking" tab
   await loadTab(page, 'Stock Tracking');
-  await page.getByText('- - Factory/Office Block/Room').first().waitFor();
+
+  await page.getByText('Factory/Office Block/Room').first().waitFor();
   await page.getByRole('link', { name: 'Widget Assembly' }).waitFor();
   await page.getByRole('cell', { name: 'Installed into assembly' }).waitFor();