fix(fs): `writeFile` create file by default (#2846)

.changes/write-readable-stream-create.md

@@ -0,0 +1,6 @@
+---
+fs: patch
+fs-js: patch
+---
+
+Fix `writeFile` doesn't create a new file by default when the data is a `ReadableStream`

plugins/fs/guest-js/index.ts

@@ -1074,7 +1074,7 @@ async function writeFile(
   }
 
   if (data instanceof ReadableStream) {
-    const file = await open(path, options)
+    const file = await open(path, { create: true, ...options })
     const reader = data.getReader()
 
     try {