ComponentSource robustness: add `ComponentSourceTestBase::testSettings()`

Overview

\Drupal\Tests\experience_builder\Kernel\Config\ComponentTest::testComponentCreation() was first created for SDC only. Then JS components were added to it.

This is partially superseded by ComponentSourceTestBase::testDiscovery(), but that tests only the auto-creation of the Component config entity, not the settings (default_settings for block components, prop_field_definitions for SDC and JS components) of the created Component config entity.

#3501290: Introduce unit test coverage for both ComponentSource plugins (Block + SDC) added ComponentSourceTestBase with only 3 mandatory test methods:

1. ::testDiscovery()
2. ::testGetReferencedPluginClass() (which @depends on the first one)
3. ::testRenderComponentLive() (which @depends on the first one)

Proposed resolution

1. Add a 4th mandatory test method:
   

     /**
      * @depends testDiscovery
      */
     public function testSettings(array $component_ids): void;
   

   to ComponentSourceTestBase

2. Remove ComponentTest::testComponentCreation()

User interface changes

None.