fix: support hydrating elements with properties whose getters throw (#13211)

Fixes #10824
If during hydration a getter of a custom element was called, and that getter throwed, hydration would fail - this makes it not do that

packages/svelte/src/internal/client/dom/elements/attributes.js

@@ -136,7 +136,13 @@ export function set_xlink_attribute(dom, attribute, value) {
  */
 export function set_custom_element_data(node, prop, value) {
 	if (prop in node) {
-		var curr_val = node[prop];
+		// Reading the prop could cause an error, we don't want this to fail everything else
+		try {
+			var curr_val = node[prop];
+		} catch {
+			set_attribute(node, prop, value);
+			return;
+		}
 		var next_val = typeof curr_val === 'boolean' && value === '' ? true : value;
 		if (typeof curr_val !== 'object' || curr_val !== next_val) {
 			node[prop] = next_val;

packages/svelte/tests/hydration/samples/custom-element-with-settable-only-property/main.svelte

@@ -0,0 +1,16 @@
+<script module>
+	if (!customElements.get('custom-element-with-settable-only-property')) {
+		customElements.define('custom-element-with-settable-only-property', class CustomElement extends HTMLElement {
+			set prop(n) {
+				this.value = n;
+			}
+
+			get prop() {
+				// invoking this getter shouldn't make hydration fail
+				throw new Error('This value is not gettable');
+			}
+		});
+	}
+</script>
+
+<custom-element-with-settable-only-property prop="8"></custom-element-with-settable-only-property>