Docs: Prevent JSON-encoding example Blueprints twice – that breaks th…

…e live examples

Closes #924

packages/docs/site/src/components/Blueprints/BlueprintRunButton.tsx

@@ -18,7 +18,7 @@ export function BlueprintRunButton({ blueprint }) {
 		);
 	}
 	const url = `https://playground.wordpress.net/?mode=seamless#${btoa(
-		JSON.stringify(blueprint)
+		typeof blueprint === 'string' ? blueprint : JSON.stringify(blueprint)
 	)}`;
 	return (
 		<iframe