Fix analyze_code to use the proper PR number (#46548)

Summary:
Analyze code was still using the CIRCLECI env variable to retrieve the PR number.
This change uses the github one and also removes a duplicated flow check

## Changelog:
[Internal] - Remove duplicated flow check and use gh PR number rather than CircleCI one

Pull Request resolved: https://github.com/facebook/react-native/pull/46548

Test Plan: Tested locally and in CI

Reviewed By: NickGerleman

Differential Revision: D62883758

Pulled By: cipolleschi

fbshipit-source-id: 0c7e97ea9caf4465972424e0b69a899ecfd07095

.github/actions/lint/action.yml

@@ -23,6 +23,7 @@ runs:
       run: yarn lint-ci
       env:
         GITHUB_TOKEN: ${{ inputs.github-token }}
+        GITHUB_PR_NUMBER: ${{ github.event.number }}
     - name: Lint code
       shell: bash
       run: ./scripts/circleci/exec_swallow_error.sh yarn lint --format junit -o ./reports/junit/eslint/results.xml