refactor: drop imports the builder no longer uses

scripts/generate_pack.py

@@ -40,8 +40,6 @@ from common import (
     build_zip_contents_index,
     compute_hashes,
     expand_directory_entries,
-    expand_platform_declared_names,
-    fetch_large_file,
     filter_systems_by_target,
     group_identical_platforms,
     list_emulator_profiles,
@@ -54,10 +52,8 @@ from common import (
     load_emulator_profiles,
     load_platform_config,
     MANUFACTURER_PREFIXES,
-    parse_md5_list,
     require_yaml,
     ProfileSelectionError,
-    resolve_local_file,
     sanitize_pack_path,
     select_emulator_profiles,
     system_core_reach,