[#225] Restore invalid_obj check

Signed-off-by: a.berezin <a.berezin@yadro.com>

src/frostfs_testlib/load/load_verifiers.py

@@ -108,6 +108,8 @@ class LoadVerifier:
             invalid_objects = verify_metrics.read_failed_iterations
             total_left_objects = load_metrics.write_success_iterations - delete_success
 
+            if invalid_objects > 0:
+                issues.append(f"There were {invalid_objects} verification fails (hash mismatch).")
             # Due to interruptions we may see total verified objects to be less than written on writers count
             if abs(total_left_objects - verified_objects) > writers:
                 issues.append(