Fix media extraction when video_versions is null

[subzeroid]

Summary

• handle video_versions: null in media, resource, direct media, and story extractors
• add a public media regression test for current xdt_api__v1__media__shortcode__web_info payloads with null video versions

Notes

• Related to [BUG] #2713. This fixes the crash/LoginRequired fallback path for null video_versions.
• I checked current web bundles/HAR/APK paths and did not find a public anonymous doc_id that restores Reels view/play counts; authenticated private media/{pk}/info/ remains the verified source for play_count.

Tests

• PYTHONDONTWRITEBYTECODE=1 .venv/bin/pytest -q tests/regression/test_public.py::PublicRegressionTestCase::test_media_info_handles_web_info_payload_with_null_video_versions tests/regression/test_public.py::PublicRegressionTestCase::test_media_info_gql_extracts_current_web_info_payload tests/regression/test_media.py::MediaInfoV2RegressionTestCase::test_extract_media_v1_normalizes_video_view_count
• PYTHONDONTWRITEBYTECODE=1 .venv/bin/pytest -q tests/regression/test_public.py tests/regression/test_media.py
• PYTHONDONTWRITEBYTECODE=1 .venv/bin/ruff check instagrapi/extractors.py tests/regression/test_public.py
• git diff --check