[plugin] Mandatory plugins (#10094)

* Add setting for "mandatory" plugins

* Add 'is_active' method to PluginConfig model

* Check against plugin config object by priority

* Prevent plugin from reporting its own 'active' status

* Refactor get_plugin_class for LabelPrint endpoint

* Fix typo

* Mark internal plugin methods as "final"

- Prevent plugins from overriding them

* Enhanced checks for bad actor plugins

* Enhanced unit test for plugin install via API

* Playwright tests for plugin errors

* Test that builtin mandatory plugins are always activated

* Force mandatory plugins to be marked as active on load

* API unit tests

* Unit testing for plugin filtering

* Updated playwright tests

- Force one extra plugin to be mandatory in configuration

* Adjust unit tests

* Updated docs

* Tweak unit test

* Another unit test fix

* Fix with_mixin

- Checking active status first is expensive...

* Make with_mixin call much more efficient

- Pre-load the PluginConfig objects
- Additional unit tests
- Ensure fixed query count

* Fix the 'is_package' method for PluginConfig

* Tweak unit test

* Make api_info endpoint more efficient

- with_mixin is now very quick

* Run just single test

* Disable CI test

* Revert changes to CI pipeline

* Fix typo

* Debug for test

* Style fix

* Additional checks

* Ensure reload

* Ensure plugin registry is ready before running unit tests

* Fix typo

* Add debug statements

* Additional debug output

* Debug logging for MySQL

* Ensure config objects are created?

* Ensure plugin registry is reloaded before running tests

* Remove intentional failure

* Reset debug level

* Fix CI pipeline

* Fix

* Fix test mixins

* Fix test class

* Further updates

* Adjust info view

* Test refactoring

* Fix recursion issue in machine registry

* Force cache behavior

* Reduce API query limits in testing

* Handle potential error case in with_mixin

* remove custom query time code

* Prevent override of is_mandatory()

* Prevent unnecessary reloads

* Tweak unit tests

* Tweak mandatory active save

* Tweak unit test

* Enhanced unit testing

* Exclude lines from coverage

* (final)? cleanup

* Prevent recursive reloads

---------

Co-authored-by: Matthias Mair <code@mjmair.com>

src/frontend/tests/pui_plugins.spec.ts

@@ -137,6 +137,18 @@ test('Plugins - Functionality', async ({ browser }) => {
   await page.getByRole('menuitem', { name: 'Deactivate' }).click();
   await page.getByRole('button', { name: 'Submit' }).click();
   await page.getByText('The plugin was deactivated').waitFor();
+
+  // Check for custom "mandatory" plugin
+  await clearTableFilters(page);
+  await setTableChoiceFilter(page, 'Mandatory', 'Yes');
+  await setTableChoiceFilter(page, 'Sample', 'Yes');
+  await setTableChoiceFilter(page, 'Builtin', 'No');
+
+  await page.getByText('1 - 1 / 1').waitFor();
+  await page
+    .getByRole('cell', { name: 'SampleLocatePlugin' })
+    .first()
+    .waitFor();
 });
 
 test('Plugins - Panels', async ({ browser, request }) => {