fix: prevent loops in postbuild analysis phase (#14450)

It is currently possible for a chunk to import chunks that import
itself. I'm not exactly sure where this occurs or why as I can't
reproduce it in a simple repository, but a simple fix is to prevent
importing already visited chunks.

Helps with #14444 though doesn't fix the underlying issue

Author: vipero07

.changeset/curvy-icons-fall.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: prevent loops in postbuild analysis phase

packages/kit/src/core/postbuild/analyse.js

@@ -255,8 +255,12 @@ function list_features(route, manifest_data, server_manifest, tracked_features)
 		manifest_data.routes.find((r) => r.id === route.id)
 	);
 
+	const visited = new Set();
 	/** @param {string} id */
 	function visit(id) {
+		if (visited.has(id)) return;
+		visited.add(id);
+
 		const chunk = server_manifest[id];
 		if (!chunk) return;