Issue #3438949 by just_like_good_vibes, pdureau: Field Formatters: Code quality improvments

...riber/UiPatternsFieldFormattersEntitySchemaSubscriber.php

...rc/Plugin/Derivative/FieldPropertiesSourceDeriverBase.php

...rc/Plugin/Field/FieldFormatter/ComponentFormatterBase.php

.../src/Plugin/UiPatterns/Source/EntityReferenceFormBase.php

...Plugin/UiPatterns/Source/FieldFormatterFormSourceBase.php

...rc/Plugin/UiPatterns/Source/FieldPropertiesSourceBase.php

...rc/Plugin/UiPatterns/Source/FieldPropertiesSourceProp.php

...rc/Plugin/UiPatterns/Source/FieldPropertiesSourceSlot.php

...UiPatterns/Source/UiPatternsFieldFormattersSourceBase.php

...patterns_field_formatters/tests/src/Kernel/PluginTest.php

...patterns_field_formatters/tests/src/Kernel/RenderTest.php

...rs/tests/src/Kernel/UIPatternsFieldFormattersTestBase.php