Skip building HotROD for all platforms for pull requests

[Charan-Sharan]

Which problem is this PR solving?

• This PR address issue Skip building HotROD for all platforms for pull requests #5743

Description of the changes

• To Skip building HotROD for all platforms for pull requests, We are adding BUILD_FLAGS=-l -p linux/amd64 in
  .github/workflows/ci-hotrod.yml while executing scripts/hotrod-integration-test.sh.
  Where,
  • -l for local build only (no pushing to public registry)
  • '-p' to only build for specified platforms and not all.

How was this change tested?

• I only tested how the flags are being passed to the script file.
• GitHub Actions related stuff is yet to be tested.

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[yurishkuro]

@Charan-Sharan thanks for contributing. We went with an earlier PR #5765