chore: fix eslint wasn't running in test dir (#11036)

This PR fixes 2 eslint config issues that prevented it from running in our test dir

- spec files were ignored by the root eslint config. This should have only ignored spec files within our packages, as they are ignored by the respective package tsconfigs
- defining the payload plugin crashed eslint in our test dir, as it was already defined in the root eslint config it was inheriting

eslint.config.js

@@ -19,7 +19,7 @@ export const defaultESLintIgnores = [
   '**/build/',
   '**/node_modules/',
   '**/temp/',
-  '**/*.spec.ts',
+  '**/packages/*.spec.ts',
   'next-env.d.ts',
   '**/app',
 ]