fix: improve unstate handling of non enumerable properties (#10348)

* fix: improve unstate handling of non enumerable properties

* Update packages/svelte/src/internal/client/proxy.js

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>

.changeset/wise-radios-exercise.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: improve unstate handling of non enumerable properties

packages/svelte/src/internal/client/proxy.js

@@ -84,10 +84,11 @@ function unwrap(value, already_unwrapped = new Map()) {
 		} else {
 			/** @type {Record<string | symbol, any>} */
 			const obj = {};
-			const keys = object_keys(value);
+			const keys = Reflect.ownKeys(value);
 			const descriptors = get_descriptors(value);
 			already_unwrapped.set(value, obj);
 			for (const key of keys) {
+				if (key === STATE_SYMBOL || (DEV && key === READONLY_SYMBOL)) continue;
 				if (descriptors[key].get) {
 					define_property(obj, key, descriptors[key]);
 				} else {