i18n: Extract Control accessibility name/description in POT generator

Control nodes' `accessibility_name` and `accessibility_description`
properties are passed through `tr()` at runtime, but were not included
in the list of properties extracted by the packed scene translation
parser plugin. This caused them to be silently omitted from generated
.pot files, making it impossible to translate them.

Fixes #115366.

editor/translations/packed_scene_translation_parser_plugin.cpp

@@ -230,6 +230,8 @@ PackedSceneEditorTranslationParserPlugin::PackedSceneEditorTranslationParserPlug
 	lookup_properties.insert("filters");
 	lookup_properties.insert("script");
 	lookup_properties.insert("item_*/text");
+	lookup_properties.insert("accessibility_name");
+	lookup_properties.insert("accessibility_description");
 
 	// Exception list (to prevent false positives).
 	exception_list.insert("LineEdit", { "text" });