Fix test Vite config helper

Author: markdalgleish

integration/helpers/vite.ts

@@ -109,8 +109,12 @@ export const viteConfig = {
               },
             }
           : undefined,
-        assetsInlineLimit: ${assetsInlineLimit ?? "undefined"},
-        assetsDir: ${assetsDir ?? "undefined"},
+        assetsInlineLimit: ${
+          assetsInlineLimit !== undefined
+            ? JSON.stringify(assetsInlineLimit)
+            : "undefined"
+        },
+        assetsDir: ${assetsDir ? JSON.stringify(assetsDir) : "undefined"},
       },
     `;
   },