Pass icon to AdminSnippetChooser in SnippetViewSet.register_chooser_widget()

This effectively sets the chooser widget icon to use SnippetViewSet.icon

wagtail/snippets/views/chooser.py

@@ -72,4 +72,4 @@ class SnippetChooserViewSet(ChooserViewSet):
 
     @cached_property
     def widget_class(self):
-        return AdminSnippetChooser(model=self.model)
+        return AdminSnippetChooser(model=self.model, icon=self.icon)

wagtail/snippets/widgets.py

@@ -13,7 +13,6 @@ from wagtail.telepath import register
 
 class AdminSnippetChooser(BaseChooser):
     display_title_key = "string"
-    icon = "snippet"
     classname = "snippet-chooser"
     js_constructor = "SnippetChooser"