Exclude tests directory from package.json files (#795)

## Description

This PR excludes `tests` directory from publishing list on npm.

### Introduces a breaking change?

- [ ] Yes
- [x] No

### Type of change

- [ ] Bug fix (change which fixes an issue)
- [ ] New feature (change which adds functionality)
- [ ] Documentation update (improves or adds clarity to existing
documentation)
- [x] Other (chores, tests, code style improvements etc.)

### Tested on

- [ ] iOS
- [ ] Android

### Testing instructions

Run `npm pack --dry-run` to check if `tests` directory is not included
anymore.

### Screenshots

<!-- Add screenshots here, if applicable -->

### Related issues

<!-- Link related issues here using #issue-number -->

### Checklist

- [x] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have updated the documentation accordingly
- [x] My changes generate no new warnings

### Additional notes

<!-- Include any additional information, assumptions, or context that
reviewers might need to understand this PR. -->

Author: msluszniak

packages/react-native-executorch/package.json

@@ -14,6 +14,7 @@
     "ios",
     "cpp",
     "common",
+    "!common/rnexecutorch/tests",
     "*.podspec",
     "third-party/include",
     "third-party",