NPM: Improve package validation (#112426)

* update validation script to run all checks, but fail if any fail

* fix package validation

* reduce comment

scripts/prepare-npm-package.js

@@ -34,6 +34,7 @@ try {
   // Fix for @grafana/i18n so eslint-plugin can be imported by consumers
   if (pkgJson.content.name === '@grafana/i18n') {
     exports['./eslint-plugin'] = {
+      types: './dist/eslint/index.d.ts',
       import: './dist/eslint/index.cjs',
       require: './dist/eslint/index.cjs',
     };