Connect Ruby tests with CircleCI (#33747)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/33747

This Diff connects the ruby tests setup with CircleCI, making sure that we are executing the same script in Sandcastle and CircleCI.

At the moment, the scripts runs somedummy tests to make sure that everything works.

## Changelog
[iOS][Changed] - Add ruby tests to circleci

Reviewed By: dmitryrykun

Differential Revision: D36091716

fbshipit-source-id: c432e5f8b5269754db2b7ec278b159dcedf3b3b9

.circleci/config.yml

@@ -452,8 +452,12 @@ jobs:
       - checkout
       - setup_artifacts
       - setup_ruby
+      - run:
+          name: Run Ruby Tests
+          command: |
+            cd scripts/cocoapods
+            sh run_tests.sh
       - run_yarn
-
       - run: |
           cd packages/rn-tester
           bundle check || bundle install