remove errant prepublishOnly script (#7893)

Author: Rich-Harris

.changeset/soft-ladybugs-drum.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Remove prepublishOnly script

packages/kit/package.json

@@ -60,7 +60,6 @@
 		"check": "tsc",
 		"check:all": "tsc && pnpm -r --filter=\"./**\" check",
 		"format": "pnpm lint --write",
-		"prepublishOnly": "pnpm build",
 		"test": "pnpm test:unit && pnpm test:integration",
 		"test:integration": "pnpm -r --workspace-concurrency 1 --filter=\"./test/**\" test",
 		"test:unit": "uvu src \"(spec\\.js|test[\\\\/]index\\.js)\"",