Fixes the UmbSubmittableTreeEntityWorkspaceContext token discriminator (#19475)

use correct property name in discriminator

Author: madsrasmussen

src/Umbraco.Web.UI.Client/src/packages/core/workspace/contexts/tokens/submittable-tree-entity-workspace.context-token.ts

@@ -9,5 +9,5 @@ export const UMB_SUBMITTABLE_TREE_ENTITY_WORKSPACE_CONTEXT = new UmbContextToken
 	'UmbWorkspaceContext',
 	undefined,
 	(context): context is UmbSubmittableTreeEntityWorkspaceContext =>
-		'requestSubmit' in context && 'createUnderParent' in context,
+		'requestSubmit' in context && '_internal_createUnderParent' in context,
 );