Skip OpenSSF Scorecard workflow on forks

[antonwolfy]

The OpenSSF Scorecard workflow fails on forks with validating options: only default branch is supported, because Scorecard only runs against a repository's default branch and forks typically push to / have a different default branch than the upstream repo.

This PR adds a job-level guard so the analysis job is skipped in forks and only runs on the upstream repository.

• Have you provided a meaningful PR description?
• Have you added a test, reproducer or referred to an issue with a reproducer?
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?
• Have you checked performance impact of proposed changes?
• Have you added documentation for your changes, if necessary?
• Have you added your changes to the changelog?

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/pull/3047/index.html

[github-actions]

Array API standard conformance tests for dpnp=0.21.0dev7=py314ha0e2e8e_2 ran successfully.
Passed: 1375
Failed: 0
Skipped: 7

[coveralls]

coverage: 78.48% (-0.003%) from 78.483% — fix/skip-scorecard-on-forks into master