Fix literal wrapping with black profile

[paulkagiri]

Summary

• account for the assignment prefix when formatting sorted literals
• use vertical hanging wrapping with trailing commas for black-style literal sorting
• add regression coverage for tuple sorting with the black profile

Fixes #1815

Tests

• python -m pytest tests/unit/test_literal.py -q
• python -m black --target-version py312 --check isort/literal.py tests/unit/test_literal.py
• python -m ruff check isort/literal.py tests/unit/test_literal.py
• git diff --check