Implement inactivity scores ef tests unstable (#8807)

fixes issue #8750


  This PR enables the inactivity_scores reward EF tests from v1.7.0-alpha.2.

- Enabled Tests: Added the inactivity_scores handler to the rewards test suite.
- Fork Filtering: Updated the runner to execute these tests only on supported forks (Altair onwards), preventing directory-not-found errors on earlier forks.
- CI Coverage: Removed exclusions in the file access check script to ensures all new test vectors are fully tracked.


Co-Authored-By: romeoscript <romeobourne211@gmail.com>

Co-Authored-By: Eitan Seri-Levi <eserilev@gmail.com>

Co-Authored-By: Michael Sproul <michael@sigmaprime.io>

testing/ef_tests/check_all_files_accessed.py

@@ -70,8 +70,6 @@ excluded_paths = [
     # Ignore full epoch tests for now (just test the sub-transitions).
     "tests/.*/.*/epoch_processing/.*/pre_epoch.ssz_snappy",
     "tests/.*/.*/epoch_processing/.*/post_epoch.ssz_snappy",
-    # Ignore inactivity_scores tests for now (should implement soon).
-    "tests/.*/.*/rewards/inactivity_scores/.*",
     # Ignore KZG tests that target internal kzg library functions
     "tests/.*/compute_verify_cell_kzg_proof_batch_challenge/.*",
     "tests/.*/compute_challenge/.*",