Set overriding legacy essays to be default like we said we would

This is required for new PECE essays to work as expected.

Without this, the essay is not shown and there's no way to fix
(for a content editor).

Ref #515

config/field.field.node.pece_essay.field_override_legacy_with_new.yml

@@ -13,7 +13,9 @@ label: 'Override legacy essay'
 description: 'When turned on, the legacy display of the essay will be replaced with the new customizable essay layout. When turned off, legacy content from PECE version 1 will be displayed when viewing the essay.'
 required: false
 translatable: false
-default_value: {  }
+default_value:
+  -
+    value: 1
 default_value_callback: ''
 settings:
   on_label: 'On'