Consolidate package checks into one Jest test

Summary:
Simplify/unify various mechanisms for the monorepo's package invariants.

These checks were previously scattered:
- `private/monorepo-tests` package (manifest field checks)
- `.github/workflow-scripts/lint_files.sh` (`.npmignore` ban)
- `react-native/eslint-plugin-monorepo` (manifest field checks — duplicated)

This folds everything into `scripts/monorepo-tests/__tests__/check-packages-test.js`. A plain Jest test is the most extensible home for future checks.

Changelog: [Internal]

Differential Revision: D111471313

Author: huntie

.eslintrc.js

@@ -61,12 +61,6 @@ module.exports = {
       files: ['package.json'],
       parser: 'jsonc-eslint-parser',
     },
-    {
-      files: ['package.json'],
-      rules: {
-        '@react-native/monorepo/react-native-manifest': 'error',
-      },
-    },
     {
       files: ['flow-typed/**/*.js', 'packages/react-native/flow/**/*'],
       rules: {

.github/workflow-scripts/lint_files.sh

@@ -453,9 +453,6 @@ jobs:
         uses: ./.github/actions/setup-node
       - name: Install dependencies
         uses: ./.github/actions/yarn-install
-      - name: Lint file structure
-        shell: bash
-        run: ./.github/workflow-scripts/lint_files.sh
       - name: Run shellcheck
         shell: bash
         run: ./.github/workflow-scripts/analyze_scripts.sh

.github/workflows/test-all.yml

@@ -15,7 +15,6 @@ exports.rules = {
   'no-react-named-type-imports': require('./rules/no-react-named-type-imports'),
   'no-react-native-imports': require('./rules/no-react-native-imports'),
   'no-react-node-imports': require('./rules/no-react-node-imports'),
-  'react-native-manifest': require('./rules/react-native-manifest'),
   'require-extends-error': require('./rules/require-extends-error'),
   'sort-imports': require('./rules/sort-imports'),
   'valid-flow-typed-signature': require('./rules/valid-flow-typed-signature'),