fix(svelte): unmount islands properly on navigation (#8448)

Author: natemoo-re

.changeset/sweet-sheep-sell.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/svelte': patch
+---
+
+Fix potential memory leak when component is unmounted

packages/integrations/svelte/client.js

@@ -3,9 +3,9 @@ const noop = () => {};
 let originalConsoleWarning;
 let consoleFilterRefs = 0;
 
-export default (target) => {
+export default (element) => {
 	return (Component, props, slotted, { client }) => {
-		if (!target.hasAttribute('ssr')) return;
+		if (!element.hasAttribute('ssr')) return;
 		const slots = {};
 		for (const [key, value] of Object.entries(slotted)) {
 			slots[key] = createSlotDefinition(key, value);
@@ -15,7 +15,7 @@ export default (target) => {
 			if (import.meta.env.DEV) useConsoleFilter();
 
 			const component = new Component({
-				target,
+				target: element,
 				props: {
 					...props,
 					$$slots: slots,