Fix variadic ParamSpec expansion crash

[KirschBluteX]

Fixes #21778.

ExpandTypeVisitor.visit_parameters previously expanded parameter types independently from their kinds and names. A starred Unpack[TypeVarTuple] could therefore reach TypeVarTuple expansion with a concrete tuple replacement and raise NotImplementedError.

This change expands a direct starred TypeVarTuple unpack while updating argument types, kinds, and names in lockstep. Concrete tuple items become positional parameters, while a residual variadic unpack remains starred.

The regression test covers the reported ParamSpec-based context-manager decorator and verifies both the with-target type and the decorated call type.

Tests:

• python -m pytest -n0 mypy/test/testcheck.py::TypeCheckSuite::check-parameter-specification.test
• python -m pytest -n0 mypy/test/testcheck.py::TypeCheckSuite::check-typevar-tuple.test -k "ParamSpec or Unpack"
• python -m pytest -n0 mypy/test/testtypes.py -k expand
• python -m mypy --config-file mypy_self_check.ini mypy/expandtype.py
• python -m ruff check mypy/expandtype.py
• Targeted pre-commit hooks: trailing-whitespace, end-of-file-fixer, black, ruff-check, codespell

[github-actions]

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅

[TheMuffinMan1320]

Looks good!