Resolve duplicate test name in test_deal_entry.py (ar-r82f.19)

[atc964]

Summary

Resolves bead ar-r82f.19. The file tests/unit/test_deal_entry.py had two functions named test_deal_data_includes_v2_fields_as_top_level_keys (lines 438 and 481). Python silently shadowed the first definition with the second, meaning the line-438 test never executed. PR #95's lint sweep masked the F811 warning with # noqa: F811 to keep its scope pure; this PR fixes the real bug.

What changed

• Deleted the redundant duplicate test at line 481.
• Removed the # noqa: F811 marker on the same line.

The two tests were functional duplicates:

• Both imported the same ManualDealEntry / create_manual_deal from ad_buyer.tools.deal_library.deal_entry.
• Both built a ManualDealEntry with the same v2 fields (only the display_name and description string values differed).
• Both asserted that data["seller_org"], data["seller_domain"], data["seller_type"], data["buyer_org"], data["buyer_id"], data["price_model"], data["fixed_price_cpm"], data["bid_floor_cpm"], data["currency"], data["media_type"], data["description"] matched the supplied entry.

The retained test (line 438) is the canonical/newer version and is strictly stronger: it adds assert "metadata" not in data, which the deleted variant did not check. git blame confirmed line 438 was added in commit 633d813 (2026-03-25 14:07) after the now-removed variant in commit 0bf2992 (2026-03-25 13:43); the newer test was the intended replacement that simply never deleted its predecessor.

Test plan

• python -c "import ast; ast.parse(open('tests/unit/test_deal_entry.py').read())" -- syntax OK
• Duplicate name check: grep "^def test_\|^ def test_" tests/unit/test_deal_entry.py | sort | uniq -c -- no duplicates
• ruff check tests/unit/test_deal_entry.py -- all checks passed
• CI test job runs and the previously-shadowed test now executes (look for test_deal_data_includes_v2_fields_as_top_level_keys in pytest output)
• No new lint warnings

bead: ar-r82f.19