fix: support sequence metric attributes in view aggregation keys

[naveenvenk17]

Fixes #3750.

Summary

• Use the SDK's attribute-key helper for metric view aggregation keys instead of frozenset(attributes.items()).
• Normalize sequence-valued attributes to tuples for the private aggregation key while preserving the original datapoint attributes.
• Broaden the existing get_dict_as_key helper from list values to non-string sequence values.
• Add a regression test for list and tuple metric attributes.

Evidence

• .tox\\py312-test-opentelemetry-sdk\\Scripts\\pytest.exe opentelemetry-sdk\\tests\\metrics\\test_view_instrument_match.py -q passed: 11 passed.
• uv run ruff check opentelemetry-sdk\\src\\opentelemetry\\sdk\\metrics\\_internal\\_view_instrument_match.py opentelemetry-sdk\\src\\opentelemetry\\sdk\\util\\__init__.py opentelemetry-sdk\\tests\\metrics\\test_view_instrument_match.py passed.
• .tox\\lint-opentelemetry-sdk\\Scripts\\pylint.exe opentelemetry-sdk\\src\\opentelemetry\\sdk\\metrics\\_internal\\_view_instrument_match.py opentelemetry-sdk\\src\\opentelemetry\\sdk\\util\\__init__.py opentelemetry-sdk\\tests\\metrics\\test_view_instrument_match.py passed: 10.00/10.
• Earlier full SDK tox run for this branch with uv run tox -e py312-test-opentelemetry-sdk -- opentelemetry-sdk/tests/metrics/test_view_instrument_match.py passed: 1098 passed, 13 skipped.
• git diff --check passed.

[linux-foundation-easycla]

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• ✅ login: naveenvenk17 / name: naveenvenk17 (dcb6629)