Fix error messages when importing .keystone/config.js (#9359)

Co-authored-by: Daniel Cousens <413395+dcousens@users.noreply.github.com>

.changeset/slimy-files-appear.md

@@ -0,0 +1,5 @@
+---
+'@keystone-6/core': patch
+---
+
+Fix misleading error messages when importing `.keystone/config.js`

packages/core/src/scripts/utils.ts

@@ -1,4 +1,5 @@
 import { getBuiltKeystoneConfigurationPath } from '../lib/createSystem'
+import fs from 'node:fs/promises'
 
 export class ExitError extends Error {
   code: number
@@ -10,13 +11,10 @@ export class ExitError extends Error {
 
 // TODO: this cannot be changed for now, circular dependency with getSystemPaths, getEsbuildConfig
 export async function importBuiltKeystoneConfiguration (cwd: string) {
-  try {
-    return require(getBuiltKeystoneConfigurationPath(cwd)).default
-  } catch (err: any) {
-    if (err.code === 'MODULE_NOT_FOUND') {
-      console.error('🚨 keystone build has not been run')
-      throw new ExitError(1)
-    }
-    throw err
+  const builtConfigPath = getBuiltKeystoneConfigurationPath(cwd)
+  if (!(await fs.stat(builtConfigPath).catch(() => null))) {
+    console.error('🚨 keystone build has not been run')
+    throw new ExitError(1)
   }
+  return require(builtConfigPath).default
 }