fix(azure-functions): pass body to the context as-is (#2965)

src/presets/azure/runtime/azure-functions.ts

@@ -25,6 +25,6 @@ export async function handle(context: { res: HttpResponse }, req: HttpRequest) {
     // cookies https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-node?tabs=typescript%2Cwindows%2Cazure-cli&pivots=nodejs-model-v4#http-response
     cookies: getAzureParsedCookiesFromHeaders(headers),
     headers: normalizeLambdaOutgoingHeaders(headers, true),
-    body: body ? body.toString() : statusText,
+    body: body ?? statusText,
   };
 }